How do we obtain/catch the four guardian deities of Alola in Sun/Moon?

[TokoyamiTheDark]

I might not know on how some people managed to get the games before the release date, but I was wondering on how the four Deities can be caught or obtained. Are they gifts? Or roaming Pokemon? Something else? Just curious because I am exiced to get Tapu Koko when the games will be out.

[Guest KaliVGC]

They have set positions which you will get to know during the game and you can catch them in the post-game.

[gundam]

on each island

look for places that have ruin of something in it

something will change depending on island and the tapu you're hunting

for example: tapu bulu is on ula'whatever that island is called, its in the desert area. ruins for it are called ruins of abundance