The biggest things that you want to use SEMrush for are keyword research and competitive analysis. If you need a backlink tool Moz is superior.
Here are 3 videos, the first is a helpful FAQ they put out to help people understand the tool. The second is a nice how to and the third is how to using data mining for offpage factors. Again you can sub in Moz DA/PA for some of the offpage metrics.
https://www.youtube.com/watch?v=mjs3nwrrxXs
https://www.youtube.com/watch?v=r0eeSNVTk6Y
https://www.youtube.com/watch?v=NGuIjnmFsCw
I'm having trouble making the videos display the titles below, so here are just the 3 urls.
