For the mulligan follow this list on HS Replay: https://hsreplay.net/decks/q5Ta3GL8Saw2yuitIRs57c/#gameType=RANKED_STANDARD.
I wanted to try 2 voodo doctors, maybe swap it with broomstick. Use it now because meta may change, atm it is very strong and it was an easy and quick climb.
Overall this decks is quite easy to pilot and it is safe to play as no one is playing soul dh.
Diamond 1 to Legend video: https://youtu.be/m5B-iDEykpg