Detail walkthrough here.
Read this only if you get stuck and can not figure out how to solve the puzzle.
Edit- Adjust some steps to make this walkthrough more straight forward and easier to follow.
1. Switch to female first, pick up the student pass under the car, get in the lobby.
Use the student pass on the turnstile, unlock then walk pass it.
Go up stairs, grab the cutting tool by the stair way, then go to the room on the left.
Pick up the scissors on the desk, then use the cutting tool to cut the chain by the window.
2. Once step 1 is done, switch to male character.
Let him walk to the left, you'll find a key by the dumpster.
Climb up the ladder until you reach the top. Enter maintenance room.
Use the key on control box, then turn off the elevator.
Grab the crowbar jamming the mechanism, grab the bread nearby, then switch the control box back on.
Elevator restored, you can now use it to travel through every floors.
3. Switch back to Female character, now go to top floor by the elevator.
Take the cleaning cloth in the maintenance room (by the door), then combine it with scissor. Give the props to the cheerleader, have some fun.
4. As you had enough fun with the lady, it's time to switch to the male character.
Control Male character, use the elevator to get to the room floor (2nd floor).
Go to the room on the left, take sausage on the bed, combine with bread, hotdog acquired.
Then go to the other room at the end, use the microwave to heat up the hotdog.
Go down stairs, give the "hot hotdog" to the warden, enjoy the show.
5. Once it's done, the turnstile will be unlock permanently. Walk out of the door and take the bike with either one of the character to finish this demo.
PS. You can use the crowbar to open one of the dumpster, but it doesn't seem to serve any purpose in this demo version.