Glitch Tutorial: Outside Sandbox Map Glitch

To do the glitch, follow these steps:
# Go to code "buffyeep" and copy the room 1.
# Paste it into the same room in your private world.
# Clear your small private.
# Build whatever you want in the big private.
# Go in play mode in the big private, and build mode in the small private. Press reset pillows in the big private.
# Run into the hallway into your sandbox
# 6.5. If you do these both steps, a green outline must not happen in between it. If it does, you are going too slow and you should restart.
# When the invisible wall/trigger disappears and you're able to go in the sandbox, run back to the big private.
# Go back into the sandbox and it should be there.
# Shift map down until it's to your liking.
# Enjoy your map.
A youtube video explaining in a lot more detail