Alright so the strategy I used was I took a managarmr (you can use any decent powered creature) killed stegos and dragged a stego corpse over and got about half trust, used about 3 because the trust starts to go down after a few seconds and went on a murder spree to tame it, you don’t need to trap this thing just try to keep the stego corpses around 100 meters from the Carch and you should be fine, another thing to note is that taking damage downs the effectiveness when your riding the Carch to tame it.