"also what should I do at all in this game to go forward?"
You don't submit quests in this game to proceed. The way to move forward is to unlock the H scenes. Specifically, you have to lose to Hentai monsters in the 2nd and 3rd dungeons over and over again. (The red circle portal) Then do the hentai side quest on the main map. The more corrupted you make Ati, then it will unlock the 4 floor so you can beat the final boss.
The Green circle portal also has levels. You have to stand in the center in front of each crystal to teleport to the area. But beating them, either unlock higher levels for your characters, or development stuff for fun. I was disappointed with the green circle area not paying off. I beat all the crystal bosses there, and the big door in the back never opened. Not even after you beat the game.
There is a reset portal though, for a new play through, but I haven't tested it out yet.