You bascially type the text that you want to show up in large print and a delay. Great for “turn off oven” in 10 mins or “GO TO THE GYM YOU LAZY SACK” in 1 hour. Things you have to remind yourself of but are too lightweight for a calendar or todo.
This sequence I got from the comments is better than the OP.
PS you have to enable beta features and turn on Proxy Objects to get this to work. At least as of version b51.