Manual, course or examples

Hi, I've seen some videos where variables and parameters are used when using Fusion. I'd like to know if there's a manual or how I can learn.
For Example:

** Point(iif(time<FrameRate,0.5, iif(time<comp.RenderEnd-FrameRate,VerticalBar.Center.X-0.5,(VerticalBar.Center.X-(Width/2)))),0.5)"

** 11- ceil((time/comp.RenderEnd)*10)


thanks in advance