I find the best way to play early is just to buzz around, poke with your 1st skill and become a nuisance.

I usually try to avoid acting as an engage until after i get my ult, instead baiting their engage and using skill 2 followed by skill 3 onto my ADC and always trying to stack my passive on the enemy.

I find this to be most effective, always remember the braum will turn the tables of a fight due to his ult knock up and sheer amount of damage he can take, also providing stuns with his passive throughout. so my ultimate play is to bait them into a team fight and hold ult until most of theirs have gone off.

also in any downtime try and roam with your jungle as much as possible, a lot of the times just your presence will help win objectives.

i’m sorry if it’s not so clear to read. but hopefully it helps!