You can post on any board that is unclaimed or one that you have claimed.
Unclaimed boards
Click the email address provided to open a compose window in your default email client. The body of the email should be written in markdown (if you don't know markdown, just write naturally). Then send it. That's it!
Only emails from the address you sent from will be allowed to edit that board going forwards. When you send another email it will completely replace the previous contents of the board. See the next section for how to update pages.
Claimed boards
Claimed boards are boards you have personally claimed. To update a claimed board, just send another email to it from the same address you claimed it with. Be careful because when you send another email it will completely replace the previous contents of the board.
To make this easy, we pre-fill your email with the current markdown contents of the page.
How to find unclaimed boards
Finding a board that hasn't been claimed yet is like finding a domain name no one has purchased. You'll have to just keep trying different URLs until you find one no one has taken yet.
If you're running into issues posting or creating, check out /_troubleshooting