What they said about the addon. One thing to remember is testing for the lack of a nofollow tag is tricky business. The dev team put a lot of work into developing that addon, and it's good, just be aware that a) I don't think there is any "perfect" way of detecting it and b) in general I think a link is better than nolink. That said, have at it with the nofollow check addon.
As for training, start by checking out the youtube video's on the scrapebox channel. Then have a look here on bhw for loopline's videos. There's some good stuff there.
peace - gregs.