My younger sister got one on day 2 of valguero, heres how:

Start out however you want, she tamed dilos for protection then tamed a pteranadon.

She then took flight to the white cliffs. (Off topic, she found a unicorn :0)

She found a nest unoccopied. (Some nests in the middle of nowhere have no deinos while the nests in other areas do.) so she grabbed the egg and flew off with her ptera. You can find nests commonly in a little valley area in the white cliffs. (Dont have coordinates)