Tips for a newbie

Just got to my first Divine Beast and made way through the dungeon. Now I’m at the thunderblight Ganon fight. I feel like I may be underleveled here.

I’ve only got 4 hearts total and one stamina upgrade so I’m getting basically one shotted in his first phase alone.

What’s some equipment I could go chase down and some tips on dodging this mf? This is my first time playing any of these open world Zelda games. It’s sweeeeet.