Taming it is fairly easy. First they are unique passive tame. They do take rockarots as the second best feed from troodon kibbles. Thou the type of food you feed them doesn't affect the taming effectiveness, it's best to use their preferred food to reduce time spending on their back taming it. It's effectiveness depend solely on how many times you fall off its back. So, get sneaky and sneak up on them, put food in 0 shortcut slot. feed them the first one and move closer to ride. Look at the bottom left of the screen. When it promts to be fed again, press e to keep it calm. Beware, pressing e when it does not want treat will unmount the tame and you will lose effectiveness by a lot. It is recommened to use quetzel to bring it to your own taming pen. During the tame it will run pointlessly in any direction and may run into predators if taming in wild. If you happen to do so in the wild, take another tribe mate with you to take care of the surroundings.
Quick tip: I was trying to tame one at my house and it bucked me off and my other tames thought it was hurting me so they killed it. Long story short, put all your other tames on passive if you want to tame it at your house.