Alright so in original version before bugfix, floor 3 doesnt work. It should now. Floor 1 starts you in a central room, where 8 rooms rotate around it. The doors change based on this rotation, which is how any room can be accesed via room 1. The rotary phone will display colored buttons that correlate to room's wallpapers, and the dial rotates to match what room is where. This can be used to access the brick room which leads you to the second floor.
Second floor is simple. You get a flip-phone that makes the level go upside-down. Sometimes this triggers special effects. It's kind of just look around, do parkour, and figure out the combination lock by chance. (This combination was going to be reincorporated as a timed event later in the game for a boss, but we didn't have time to add the boss.)
Third floor involves figuring out how to dial into a correct room. The area code is on a stickynote in room 1. In order to get into any rooms besides the void on floor three, you must dial the area code first. Then, combine numbers with colored-coded text to figure out numbers to dial. this should give you a number like this (570) XXX-XXX_ . Dialing that number, then another number, then pressing down to exit the dialpad, calls up a specific room. If you found the numbers throughout the game and put them in the right order, then dialed a number of your choice, entering the room marked with a '?' takes you into a puzzle room. This usually has pieces of the phone number, scattered thoughout all 9 iterations of the room. Finally, you reach the computer, interact with it to beat the game... for now.