1. You have to have a tumblr. Register here.
2. The Miniweek takes place on January 4th-8th, the gift exchange is finalized a day later.
3. Sign-ups for the exchange end on Midnight, December 9 GMT+1 (which is December 8th, 6pm for GMT-5 and December 9th, 7am for GMT+8).
4. Details, guidance and a sign-up form.