how do i enable mastodon on my mobile phone?

Can't select chaos.social there.

I never allowed any commercial social media on my phone.

As Mastodon is self hosted open source i'd see that different here and would be ok to put that on my android phone.

so - i am trying to do that right now. I have installed the mastodon app but i need to select a community to log in and chaos.social is nothing i can put in in any way....