Indie game storeFree gamesFun gamesHorror games
Game developmentAssetsComics

1. in the forest (green door, you need the emerald fragment)

2 and 3.see the guide

where is the guide, if I may ask, also where is the emerald fragment?

You can find the Guide (Guided Walkthough) in the Help Thread here on Itch (one with the "sticky") or go to the Patreon Page and find the Guided Walkthrough (which I have been doing) and Picture Walkthrough (though this one has not been updated since 1.0, but recommended if you want pictures and not text). All 3 Questions are answered there.