I know all the modes and pentatonics, but I can't figure out where to tap when doing tapping. I struggle with this for a while, and I was unable to find any video lessons or books that cover this. Can anyone explain it to me or show me a video lesson or something? I'm going to list a few videos as a refference to what I mean:

https://www.youtube.com/watch?v=nY7GnAq6Znw // End solo at 6:02

https://www.youtube.com/watch?v=mDZuNM3HmU4 // The intro at 0:40

https://www.youtube.com/watch?v=h5BrE1Pi5cU // The solo at 4:36
Here is a vid lesson from the worlds finest mate. The first 120 secs should be enough to set you off and running.