In Ragnarok the scar is right by the volcano but not exactly on the volcano so you basically would want to fly a PT to where the scar is then you would want to go in and avoid all wyverns while trying to find an egg you would want to upgrade your PT mostly on stam and a bit on speed. Once you find the wyvern egg make sure there are no wyverns near you then grab the egg hop back on your PT before the wyverns get too close to you because they realize you stole their egg. And then go for about 20 seconds then land and make sure the wyverns did not follow you and then go incubate the egg if you don't have any wyvern milk then as long as you're baby mature speed is up high enough then you can literally just wait for it to grow up without any wyvern milk once you hatch the egg. There you go now you got your wyvern! ( I play on old ark so if you're on New ark those might not be the exact instructions)