Hearthstone mobile solo raid boss onyxia

Hello guys and girls :heart:

Iam new with this game i play less then a week,i play a mobile version and very enjoy.

I stuck and need help : in solo game
In "book of mercenaries " chapter 4/8 with varden dawngrasp. I just cant beat that annoying “broodmother”. 2 days in row i try to beat her and i cant. I tried to find guides on youtube and cant fond mobile version guide.

Could any one can give me advice how do i beat her ??

Mobile or pc the game is the same, only the visual change so any pc guide should be valid for you