How do i make it so when i click with an item, it rewards points?

To make the tool award points, you need to put a serverscript, a localscript and a remoteevent into the tool. Name the tool i.e. pointsRemote.

Then what we do next is set up the event handler for server event, aswell as a debounce to prevent them from spam clicking the tool.

After a successful click, we use PointsService:AwardPoints() to give the player one point.

Server script in the tool:

local remote = script.Parent.pointsRemote
local tool = script.Parent

local debounce = false
local interval = 1

remote.OnServerEvent:Connect(function(p)
    if debounce then return end
    debounce = true
    local plr = tool:FindFirstAncestorWhichIsA("Player") or game:GetService("Players"):GetPlayerFromCharacter(tool:FindFirstAncestorWhichIsA("Model"))
    if not plr then debounce = false return end
    if p ~= plr then --a lil security
        p:Kick("Stop firing someone else's remotes, nub exploiter")
        debounce = false
        return
    end
    game:GetService("PointsService"):AwardPoints(plr.UserId, 1)
    wait(1)
    debounce = false
end)

Localscript in the tool:

local remote = script.Parent.pointsRemote
local tool = script.Parent
tool.Activated:Connect(function()
    remote:FireServer()
end)

Now, to make their WalkSpeed increase, let's say by 1 for each 10 points, we're going to use PointsService:GetGamePointBalance() in any server script. It would be the best to have only one server script handle it.

local ps = game:GetService("PointsService")

game:GetService("Players").PlayerAdded:Connect(function(plr)
    plr.CharacterAdded:Connect(function(char)
        local hum = char:WaitForChild("Humanoid")
        hum.WalkSpeed = 16 + math.floor(ps:GetGamePointBalance(plr.UserId) / 10)
    end)
end)

local Tool = script.Parent

local Player = game.Players.LocalPlayer
local Character = Player.Character
local Mouse = Player:GetMouse()

Mouse.Button1Down:connect(function()
    while true do 
        Player.leaderstats.Points.Value = Player.leaderstats.Points.Value + 100
        Character.Humanoid.WalkSpeed = math.huge
        -- do rest
    end
end)