As a Bruno player on one of my accounts I’ll give you my build.
Berserker’s Fury > Swift Boots > Scarlet Phantom > Demon Hunter Sword > Malefic Roar > Blade of Despair
Core items are Berserker’s Fury to Demon Hunter Sword. Last two items can be changed depending on the situation. This build is for ADC and for pushing. My playstyle just involves pushing the enemy turret and not joining clash but this build also helps you in clash.
Push Playstyle Use your first skill on creeps for laning or when chasing a running opponent to slow them down or maybe to finish them off. Never use your second skill on more than one hero cause you’ll most likely die. Only use it for engaging in 1v1 when you know you can stun the enemy and kill them. When engaging a stronger opponent than you make sure there are minions around so you can use your Ultimate for that extra damage and armor reduction. I’ve killed many careless tanks with this. They ignored my ball hitting them together with the minions then I killed them when they’re half health. Use your spell when fighting 1v1 or for pushing turrets faster. Always use your second skill for running away not for engaging 1v2, 1v3, 1v4 or 1v5. Learn to hide in bushes while pushing. You don’t need to join clashes. Just push fast and escape with your 2nd skill when an enemy comes
Marksman playstyle When joining clashes always release your ultimate first then run away and let your ball do the work. Just stay at the back of the clash and hit. Always use 2nd skill for running away and never for engaging specially when you don’t have a tank. You don’t need to farm with Bruno since he can lane better than most marksman and poke enemies using his first skill. I also recommend building two mana necklaces when doing this playstyle. During clashes position yourself at the back and always remember to release your ultimate to disrupt enemy formation. When engaging enemies always use 2nd skill first to stun then basic attack enemy till they die. If they somehow survive and use flicker use 2nd skill to chase then use first skill/basic attack to finish them off.
If you have any more questions just ask away.