Hi there! Welcome to Lettuce Craft, it’s great to have you here 
This Happy Mail Craftalong is not a formal organised swap - you can simply join by chatting in the thread, and exchanging snail mail with other happy mailers. Have a look at the information in the post at the top of this thread.
If you are keen to join one of the organised craft swaps, the first thing to do is to keep visiting Lettuce Craft, and keep posting. You need to be a member for a month, and post at least 15 times, to join one of the organised swaps. All the rules for swapping are here. If you haven’t already, you can also look through the Crafty Shenanigans section of the site, hopefully that will make it a bit clearer. And just ask if you’ve got any questions, it’s a friendly place here, and we love to have new people joining in 