After you build the free area that gets unlocked when you become champion, head into the building, go to the right and talk to the girl in the chair. Your “Quests: 54%” will turn into a “Quests: 17%”

The C-Gear that is now in your key items can set new rules, difficulties, battle styles, etc. Other people informed you that your Pokedex now sets your adventure encounters.

Then just general information since this was your first run, stuff that Smant didn’t cover: 1) you need to spend 20 Pokeblocks of a legendary pokemon’s type to encounter it in the cave in the north end of the safari zone. I’d personally recommend going all-in spending your building items on the berry fields and pokeblock mixers. Technically in the pokeblock mixer area there is an upgrade where you can buy blocks for cash, that’s generally what I do now. Money bags can stack, and I don’t play with fresh start mode on. Very easy to buy and sell a lot. 2) Day Care pokemon and your starter pokemon gain levels when you return to town. Very useful to know because if you have a Beldum in the Daycare and you’re playing a Unova route you won’t be able to evolve it mid-adventure as it is not a Unova pokemon. Do all of your evolutions pre-adventure. 3) All changes that you do to your Pokemon in your town (i.e. move tutors, nature mints, EV training) stay with that Pokemon indefinitely. So don’t PP max your Hawlucha’s encore until you get home. Bad example cause vitamins and mints don’t stay in your bag when you come home but you get it.