I had a hard time finding it, too. There are many missing or misdirecting links en route.
The project page is here. The how-to-join link on that page takes you here.
The instructions for joining send you to this G2G post, where you discover, after reading a warm and inviting introduction, that they're not accepting new members pending a reorganization.
I added a Louisiana tag to my followed tags list a while back, when I first tried to join. I wondered why I hadn't seen them in my feed; turns out, while tracking down the URLs for this post, I discovered I should have added Louisiana_Families. I just now changed it. So we'll see.
If the project isn't open for business, that information really should be on the project page, which is hard enough to find, with instructions to add the tag.