This is a general tip for any mobile players looking to tame one of these: head to the central cave (located between the two mountains north of the Redwoods) with a mount of your choosing (A baryonyx is very useful), and brave the cave up until you come across a megalosaurus. Then, you can either:

A.) Kill it, take its implant, and revive it in a safe location to tame

B.) KO it then and there, and tame it while in the cave

C.) Lure it out of the cave, into a trap or just into the open, and KO it.

I would highly recommend A, although you will need to have a revival platform and a large cage around it, as well as ancient amber. For less paranoid players, taming it then and there probably won't be as much of a hassle, but I personally don't like taming things in dangerous areas. Hope this helped :)