I decided to create this guide as some puzzles are not fully understandable without a little help.
I have attached images of the individual puzzles, the photos are oriented correctly to then have the right solution
Universal Hint: Everything you need to complete every puzzle is inside the puzzle boards, you don't need to leave the room looking for clues.

You have 5 columns, one is completed, and the other 4 have one empty spot each that is the solution.
https://imgur.com/gQoESK3.jpeg
Small Hint:
You clearly need to complete the other columns to get the solution numbers so take a good look at the only column that's complete
Big Hint:
Every column adds up to 30
Solution:
1856

You have 12 colored squares with open and closed shapes inside and the solution is presented with colored squares without shapes inside.
https://imgur.com/W6Mmdvu.jpeg
Small Hint:
The plus symbols mean you need to mix colors, not numbers: yellow+blue=green
Big Hint:
You need to count the ANGLES (even if they are convex corners), NOT THE EDGES of the shapes inside the squares of the same color as the solution after you did the color mixing. (Do not count the edges as a lot of people are saying in the comments, if you count the edges the third shape is 4 instead of 3.)
Solution:
3834

You have 13 colored squares that form up an 8 on the board and on the right 4 instructions.
https://imgur.com/4STthhy.jpeg
Small Hint:
The 4 instructions need to be read from top to bottom.
Big Hint:
You need to remove the squares crossed on the right from the 8 shapes on the left to see the solutions. It's like a digital clock that's displaying an 8 and by removing squares you are turning off leds
Solution:
6539

You have a pentagon-shaped arithmancy puzzle with a 5 inside a black circle and then a 9, a 7, a 8 and a 6.
https://imgur.com/UrDOl7u.jpeg
Small Hint:
5 is the start of the puzzle.
Big Hint:
You need to subtract the first number from the next one and then subtract the result from the next number and then subtract the result from the next number ecc until you are done
Solution:
4351