A simple cut in the timeline means there is a gab in between the clips where you chose to cut the selected clip. A ripple delete is a smooth cut. It is when you make a cut and the rest of the clips moved over to make the clip smooth. No gab between clips is visable. Lifting is cutting and extracting is a ripple edit.

This is an example of an insert edit. An insert edit places a clip inbetween other clips. You may insert the clip where ever you feel it will look best. I decided to insert my clip in the middle because I felt like it would make sense to have the woman pause, get her instruction then repeat the exsercise.

This is an example of an overlay edit. With Overly you are putting an edided clip on top of the clips in the timeline isted of moving the clips over which would would produce an insert edit. You use an overlay when you just want to place it on the final clip and have it override a clip. You use insert when you want to add it onto the final product put not override over any clips.