How to Join an X-Outpost
Each X-Outpost has a "Guardian", someone who is leading the organization. You'll be able to find in the channel a place where you can sign up to join if there are still available openings.
If you sign up, make sure the Guardian confirms your spot before booking anything.
The Guardian will keep you up to date with the details. It's important that you keep the Guardian up to date should your plans change, as it could affect the entire group going.