I need my gun to be a server script but i need local player at the same time. Help?

remplace the :

local Player  = game.Players.LocalPlayer

with :

game.Players.PlayerAdded:Connect(function(player))
-- insert your code here and remplace Player with player
end)

--Edited The New Code:

game.Players.PlayerAdded:Connect(function(player)
    local Mouse = player:GetMouse()
    local k = Instance.new("Part")
    local Tool = script.Parent.Parent
    local canshoot = false

    Tool.Equipped:Connect(function()
        canshoot = true
    end)
    Tool.Unequipped:Connect(function()
        canshoot = false
    end)

    Mouse.Button1Down:Connect(function()
        if canshoot == true then
            wait(0.5)
            k.Parent = game.Workspace
            k.Color = Color3.fromRGB(1,1,1)
            k.Size = Vector3.new(0.08, 0.08, 0.08)
            k.Anchored = true
            k.CanCollide = false
            k.Position = Vector3.new(Mouse.Hit)
            k.CFrame = Mouse.Hit
            script.Parent.Shoot:Play()
            repeat  wait(.001) script.Parent.PointLight.Enabled = true until script.Parent.Shoot.Playing == false       
            if script.Parent.Shoot.Playing == false then
                script.Parent.PointLight.Enabled = false
            end
        end
    end)

    function onTouched(hit)
            local human = hit.Parent:findFirstChild("Humanoid")
            if (human ~= nil) then
                    human.Health = human.Health - 7
    if k.Touched then
        k:Destroy()
    end
            end
    end
    k.Touched:connect(onTouched)
end)