I heard about like quests or something but idk where to find it, is it in shops?

Quests are a good place to start for sure. I'd recommend starting with the Wizard, especially since right now he's the weekend quest so he's giving extra bonuses.

On that page, you can see links to all the other quests so you can try out different ones and see which you like. Sarah is designed for newer users so I'd go for those after the Wizard. You can find the quest givers on the map, but a much easier option is to add the quests widget to your sidebar on this page! That gives you a list off all quests that'll be on your sidebar for easy access on any page.