I want to make my CFrame Y value to change, and only that XYZ value to change.
Please help me with it! I've tried to code it here it is:
script.Parent.CFrame.Y = script.Parent.CFrame.Y + 20
In your situation, you'd use it like this,
script.Parent.CFrame = script.Parent.CFrame:ToWorldSpace(CFrame.new(0,20,0))