You can easily find then in high mountain-areas bring a pteradon as your back up the shoot it with tranquil arrows/darts and bring steggokibble and a few narcotics just in case. Then protect your tame so it does not fall as prey to other carnivores. Always start with a low level then once your level'd up go for the higher ones. Don't forget to bring the saddle!. And lastly please make sure your tough enough to face the surrounding area
To tame one easy all you have to do is kill something so the argent Avis can eat, and while it’s healing you must knock it out with tranq arrows or darts. If it is knocked out while healing it’ll starve immediately and it’ll tame in seconds no matter what level!
If you lose your argys go to the place that shows your character press the tames button which says how much animals you have, Look for your argys name press request, then wait. It will tp to you, if it’s alive.