where are the other 3 endings i only found ending 1/4
If you open the map you should see a lot of question marks showing puzzles you haven't been to yet. Now that you've gotten ending 1, you have all the information you need to reach all of these locations. Figuring out how to get to them is a puzzle of its own though, so don't give up!
If you get really stuck, you can always ask the hint system "What is my goal here" to see if there's more to a level than you think.