There’s a national Facebook page at: https://www.facebook.com/National.Atheist.Party
And then there are state pages. For instance, since I’m in Brooklyn, I’d join https://www.facebook.com/groups/205092406200790/
. . . except that I’m not joining it since I don’t think it’s viable, for most of the reasons discussed above. But considering how small this party is, if any forum members want to join it to try to influence it . . . well, now’s your chance.