I can't tell you how since I never played earth main. Did you check youtube though? I found a lot of helpful videos there. Just make sure they are not so old or at least they are from 4.0. If you don't find videos for earth main, change to other mains. For some ninja exams certain mains would work better than others.

Try this. This is what I used:

https://www.youtube.com/watch?v=-nDv9P2OgEM