Regarding the first task / schematic (there are multiple in the game), the numbers are next to some yellow lines, indicating the dimensions.
The square should be:
- 10 wide / tall
- 3 is the thickness
- 4 is the inner cut square wide / tall
Yes it’s definitly not for everyone and I guess a tutorial would be helpful, while the game is intentionally a bit challenging and you have to do some arithmetic in your head ;)