how do i make a Galactic Pet?

On the 6th and 7th of every month, you can go to the Coda Caves on Atebus and collect gems. There, you will be given the option to speak ltallo and do one of his quests. This simply involves collecting a variety of the gems (doesn't matter if you buy them or dig them up) Once you have them all, you can pick a pet to transform :)

thank you very much. my old brain has a hard time remembering so much stuff. thank you very much Pokeman