Welcome to GMAT Club and good luck on your test in a few weeks!
1. You do NOT need to memorize the codes. You will have a list of schools you can choose and they have names and you can either search or sort them or both. You can safely remove that from your memory and not worry about it on the test day. I frankly don't know why GMAC says to look them up. It's been confusing people for years now.
2. For the last minute tips - there are a few resources and ideas. Here is my post from a few years ago and just updated a few mins ago with better formatting (the tips are all still valid... though perhaps don't have the COVID-19 guidelines which you should familiarize yourself with the rules and if you need to wear a mask or perhaps you want to, earplugs, etc)
https://gmatclub.com/forum/what-to-do-3 ... 52506.html3. There is a Video that have been done on this 2 weeks ago but it is a bit long and goes over quite a bit of the detail:
https://www.youtube.com/watch?v=vIWv_TO7bQM