I suggest you use undo/redo to travel back and fore a couple of times to see what really happens. While doing so you may want to use the other functions we talked about earlier: rotate, zoom, transparent/stripes/solid.Using the transparent mode should give you a better insight how the more complicated cases fit together.
After you’re familiar with all this, you might want to build a sequence, undo 2 steps and, instead of pressing redo, select a different process. For example: start over, press Sedimentation - Intrusion - Faulting - Erosion, then press undo twice and then Erosion - Faulting. What is similar ? What is the difference ?