FAQ: What are Room Nicknames and Room ID's?
Nicknames are not necessary, since you can link rooms using the Room ID numbers, but that can require you to keep lots of notes as to what numbers are matched up with what rooms. You don't get to pick the numbers, since the site assigns them so they are unique over the whole server.
Nicknames can be anything from a few letters and numbers (Example: "entry4" or "Steve") or include multiple words and spaces (Example: "Enter the Cave" or "Room 144"). It is best not to make them too long since you have to enter them in each time you want to link to them. It is also smart not to just use numbers as this could confuse the system between Room ID numbers and Nicknames.
Then every time you want to link to a page you can either enter the Room ID number (if happen to you know it) or simply enter the Nickname (that you created, so it should be easier to remember). This is normally done when creating rooms.