The puzzles inside Toks dungeon are all in different rooms connected by corridors.
As you do each puzzle you will open up the route to the next puzzle.
The first puzzle you can do is the rat maze. When you have successfully completed the rat maze the doorway to the soduko room will open up. It will also open up a bridge that goes over the rat maze puzzle room, allowing you to skip the puzzle and go straight to the soduko room next time. All of the puzzles are skip-able after you have completed them for the first time.
The first 3 puzzles need to be completed and opened up in order, doing these 3 puzzles will then give you access to the dining room and from there you can choose to do the remaining puzzles in any order you wish.

Each of the puzzle guides have pictures, explanations and at least one video!
Solo mode is explained first, scroll down to find the Duo mode explanation.

There are 7 different puzzles in TOKS dungeon. You can see their locations on the map here…