Here are some Youtube videos that show how to use the Slidelock:
https://www.youtube.com/watch?v=x1hyEDLC4S8
https://www.youtube.com/watch?v=hYOoRetnlfM
Although I use my Slidelock on top of my June Tailor Shape Cut mat, I do not use it on top of my other rulers. In terms of measuring, it does not take the place of my regular rulers. It does take the place of my regular rulers for cutting.