Hosts open a challenge — send 3 Happy Mails, finish swaps, or mail Mystery packs. Join while it’s open. Every envelope you mark mailed (or completed, depending on the challenge) counts on the public wall. Home shows your count toward the goal after you join (for example 1/3). The challenge page says Do this next: pack an open swap or circle kit if you already have someone, or find a new partner. Circles and 1:1 swaps both count when the program matches.
- Join an open challenge from Challenges or Home.
- Read Do this next — pack a kit if you already have a swap or circle envelope, or find someone new in the directory.
- Mark I mailed it on the swap or circle. That count shows on the wall (Happy / Mystery challenges only count matching programs).
- When you hit the goal, cheer others on the wall. Print a letter if you want to write again.