Help with AssemblyLinearVelocity

Can somebody explain how AssemblyLinearVelocity works? I have tried using AssemblyLinearVelocity for a conveyor type part, but it never works.

What is the issue? When I use LookVector, it works, but when I use a Vector3 value, it doesn’t.

What solutions have you tried so far? I tried to use LinearVelocity constraint, till I found out that it can’t be used to make a conveyor.

This is the code I’m working on, so can somebody tell me what the problem is?

task.spawn(function()
    while true do
        local rngx = Random.new()
        local rngz = Random.new()
        local Randomx = rngx:NextInteger(8, 17)
        local Randomz = rngz:NextInteger(10, 19)

        Water.AssemblyLinearVelocity = Vector3.new(Randomx, 0, Randomz)
        print(`[Pool] Setting Velocity to {Randomx}, 0, {Randomz}.`)

        task.wait(5)
    end
end)