Man I wish I had beta, I'm no tester sadly. I've only been able to play around on the PTR a bit.
I have found one okay video though: https://www.youtube.com/watch?v=Ckya-_c06pQ
Haven't watched through this one yet but found it while I was looking for the above link again: https://www.youtube.com/watch?v=Xqi1V65rg_Y
My strategy is to google along the lines of 'disc legion beta raid' or something to that effect, then put it on videos and set it to within the last week or month.