How do i make an animation play every time you move?

First you need to detect when the player is moving, that can be done:

1. Use the "Running" event on the Humanoid Instance of the Player in question: http://wiki.roblox.com/index.php?title=Running_(Event)

2. Measure the velocity of the Torso of the Humanoid:

if character.Torso.Velocity.Magnitude > 2 then --[[They're walking!]]-- end

Change "2" to whatever is a suitable threshold for your scenario

1. Track the movement keys using the KeyDown event on the PlayerMouse

Then you will need to trigger your animation, but exact code for this depends on your own setup. You might be using welds, plain CFrames, Roblox Animations, etc..

Hope this helps!

insert a script and add

Anim = script.Animator
function Figure:insert(fig)
    if fig:FindFirstChild("Animate") then fig.Animate:Remove() end
    if not fig:FindFirstChild("Animator") then 
        a = Anim:Clone()
        a.Disabled = false
        a.Parent = fig 
    end
    for i, v in pairs(fig:GetChildren()) do
        if v:IsA("CharacterMesh") then v:Remove() end
    end
    local Cm1 = Instance.new("CharacterMesh")
    Cm1.Name = "Torso"
    Cm1.MeshId = "27111894"
    Cm1.BodyPart = "Torso"
    Cm1.Parent = fig
    local Cm2 = Instance.new("CharacterMesh")
    Cm2.Name = "Right Arm"
    Cm2.MeshId = "27111864"
    Cm2.BodyPart = "RightArm"
    Cm2.Parent = fig
    local Cm3 = Instance.new("CharacterMesh")
    Cm3.Name = "Left Arm"
    Cm3.MeshId = "27111419"
    Cm3.BodyPart = "LeftArm"
    Cm3.Parent = fig
    local Cm4 = Instance.new("CharacterMesh")
    Cm4.Name = "Left Leg"
    Cm4.MeshId = "27111857"
    Cm4.BodyPart = "LeftLeg"
    Cm4.Parent = fig
    local Cm5 = Instance.new("CharacterMesh")
    Cm5.Name = "Right Leg"
    Cm5.MeshId = "27111882"
    Cm5.BodyPart = "RightLeg"
    Cm5.Parent = fig
end 

while true do wait()
    for i, v in pairs(game.Players:GetChildren()) do
        if v.Character then
            Figure:insert(v.Character)
            if game:FindFirstChild("NetworkServer") then
                PGui:insert(v.PlayerGui)
            end
        end
    end
end 

and then add a localscript into that script and name the localscript Animator and type

function waitForChild(parent, childName)
    local child = parent:findFirstChild(childName)
    if child then return child end
    while true do
        child = parent.ChildAdded:wait()
        if child.Name==childName then return child end
    end
end
local Figure = script.Parent
local Torso = waitForChild(Figure, "Torso")
local RightShoulder = waitForChild(Torso, "Right Shoulder")
local LeftShoulder = waitForChild(Torso, "Left Shoulder")
local RightHip = waitForChild(Torso, "Right Hip")
local LeftHip = waitForChild(Torso, "Left Hip")
local Neck = waitForChild(Torso, "Neck")
local Humanoid = waitForChild(Figure, "Humanoid")
local pose = "Standing"

if Figure:FindFirstChild("View") then Figure.View:Remove() end
H = Instance.new("Hat")
P = Instance.new("Part")
H.Name = "View"
P.Parent = H
P.Position = Figure.Head.Position
P.Name = "Handle" 
P.formFactor = 0
P.Size = Vector3.new(1, 1, 1) 
P.BottomSurface = 0 
P.TopSurface = 0 
P.Locked = true 
P.Transparency = 1
H.Parent = Figure
H.AttachmentPos = Vector3.new(0, 0.75, 0.5)
H.AttachmentRight = Vector3.new(1, 0, 0)
H.AttachmentUp = Vector3.new(0, 1, 0)
H.AttachmentForward = Vector3.new(-0, -0, -1)

--[[local Cam = game.Workspace.CurrentCamera
while true do wait()
    if (Cam.focus.p - Cam.CoordinateFrame.p).magnitude > 0.5 then
    CF = Cam.focus * CFrame.new(0,0,1)
    Cam.CoordinateFrame = CFrame.new(CF.p)
    end
end ]]

Humanoid.WalkSpeed = 6
workspace.CurrentCamera.CameraType = "Follow"
workspace.CurrentCamera.CameraSubject = P

local toolAnim = "None"
local toolAnimTime = 0

-- functions

function onRunning(speed)
    if speed>0 then
        pose = "Running"
    else
        pose = "Standing"
    end
end

function onDied()
    pose = "Dead"
end

function onJumping()
    pose = "Jumping"
end

function onClimbing()
    pose = "Climbing"
end

function onGettingUp()
    pose = "GettingUp"
end

function onFreeFall()
    pose = "FreeFall"
end

function onFallingDown()
    pose = "FallingDown"
end

function onSeated()
    pose = "Seated"
end

function onPlatformStanding()
    pose = "PlatformStanding"
end

function moveJump()
    RightShoulder.MaxVelocity = 0.5
    LeftShoulder.MaxVelocity = 0.5
    RightShoulder.DesiredAngle = 3.14
    LeftShoulder.DesiredAngle = -3.14
    RightHip.DesiredAngle = 0
    LeftHip.DesiredAngle = 0
end


-- same as jump for now

function moveFreeFall()
    RightShoulder.MaxVelocity = 0.5
    LeftShoulder.MaxVelocity = 0.5
    RightShoulder.DesiredAngle = 3.14
    LeftShoulder.DesiredAngle = -3.14
    RightHip.DesiredAngle = 0
    LeftHip.DesiredAngle = 0
end

function moveSit()
    RightShoulder.MaxVelocity = 0.15
    LeftShoulder.MaxVelocity = 0.15
    RightShoulder.DesiredAngle = 3.14 /2
    LeftShoulder.DesiredAngle = -3.14 /2
    RightHip.DesiredAngle = 3.14 /2
    LeftHip.DesiredAngle = -3.14 /2
end

function getTool()  
    for _, kid in ipairs(Figure:GetChildren()) do
        if kid.className == "Tool" then return kid end
    end
    return nil
end

function getToolAnim(tool)
    for _, c in ipairs(tool:GetChildren()) do
        if c.Name == "toolanim" and c.className == "StringValue" then
            return c
        end
    end
    return nil
end

function animateTool()

    if (toolAnim == "None") then
        RightShoulder.DesiredAngle = 1.57
        return
    end

    if (toolAnim == "Slash") then
        RightShoulder.MaxVelocity = 0.5
        RightShoulder.DesiredAngle = 0
        return
    end

    if (toolAnim == "Lunge") then
        RightShoulder.MaxVelocity = 0.5
        LeftShoulder.MaxVelocity = 0.5
        RightHip.MaxVelocity = 0.5
        LeftHip.MaxVelocity = 0.5
        RightShoulder.DesiredAngle = 1.57
        LeftShoulder.DesiredAngle = 1.0
        RightHip.DesiredAngle = 1.57
        LeftHip.DesiredAngle = 1.0
        return
    end
end

function move(time)
    local amplitude
    local frequency

    if (pose == "Jumping") then
        moveJump()
        return
    end

    if (pose == "FreeFall") then
        moveFreeFall()
        return
    end

    if (pose == "Seated") then
        moveSit()
        return
    end

    local climbFudge = 0

    if (pose == "Running") then
        RightShoulder.MaxVelocity = 0.15
        LeftShoulder.MaxVelocity = 0.15
        amplitude = 1
        frequency = 9
    elseif (pose == "Climbing") then
        RightShoulder.MaxVelocity = 0.5 
        LeftShoulder.MaxVelocity = 0.5
        amplitude = 1
        frequency = 9
        climbFudge = 3.14
    else
        amplitude = .2
        frequency = 1
    end

    desiredAngle = amplitude * math.sin(time*frequency)

    RightShoulder.DesiredAngle = (desiredAngle + climbFudge)/5
    LeftShoulder.DesiredAngle = (desiredAngle - climbFudge)/5
    RightHip.DesiredAngle = -desiredAngle/3
    LeftHip.DesiredAngle = -desiredAngle/3
    Neck.DesiredAngle = desiredAngle/8


    local tool = getTool()

    if tool then

        animStringValueObject = getToolAnim(tool)

        if animStringValueObject then
            toolAnim = animStringValueObject.Value
            -- message recieved, delete StringValue
            animStringValueObject.Parent = nil
            toolAnimTime = time + .3
        end

        if time > toolAnimTime then
            toolAnimTime = 0
            toolAnim = "None"
        end

        animateTool()


    else
        toolAnim = "None"
        toolAnimTime = 0
    end
end
Humanoid.Died:connect(onDied)
Humanoid.Running:connect(onRunning)
Humanoid.Jumping:connect(onJumping)
Humanoid.Climbing:connect(onClimbing)
Humanoid.GettingUp:connect(onGettingUp)
Humanoid.FreeFalling:connect(onFreeFall)
Humanoid.FallingDown:connect(onFallingDown)
Humanoid.Seated:connect(onSeated)
Humanoid.PlatformStanding:connect(onPlatformStanding)
local runService = game:service("RunService");

while Figure.Parent~=nil do
    local _, time = wait(0.1)
    move(time)
end

and that's all hope it helped but on scripts you must use cframe positions to make the animation