a good trap to make is one stone foundation with three walls and a doorframe on the bottom and 4 door frames without doors in them on top of the first walls with a roof on top of the door frames. when the bronto comes after you, jump up and shoot it until it starts torpor running. then you leave the 1x1 and chase it down until you knock it out
A tip make a stone foundation and 3 stone walls and 5 stone door Frames. Place the foundation make a way to go in then place stone wall now place a door Frame on top on every stone wall brontosaurus can't damage stone. Now just do inside and start shooting with trank arrows. Easy tame I take a lvl 290 with this method.
Bronto are slow just shoot shocks or tranqs and walk backwards. Use large rocks to jam them they struggle to cross non flat terrain. Use EXCEPTIONAL kibble to tame high levels or you will be waiting 5-10 min even from starve using berries or veg.
Bronto can carry as many people as you like with or without platform saddle aslong as weight limit is not exceeded. (There is no seat for passangers to mount)