How would i move a model using vector3 slowly?

Your best bet would be to use a For loop.

For example,

for i = 1, 20 do
    script.Parent.CFrame = script.Parent.CFrame * CFrame.new(.2, 0, 0)
    wait()
end

This, in a script parented to the part, will move the parent brick 1/5 of a stud every ~1/30th of a second, 20 times. Thus, moving the part 8 studs.

If you're looking to only use Vector3 values, here is another example.

for i = 1, 20 do
    script.Parent.Position = script.Parent.Position + Vector3.new(.2, 0, 0)
    wait()
end

Same script.

Hopefully my overuse of examples explains this well.