If you are on this post : click on the name of the community at the top (above the post title). Then the community opens and you can click "subscribe". In some communities you need to be approved, then you see "pending".
Right, sorry, I was misremembering my issue. There's no search bar on Jerboa, so I can't find new communities through the app unless they happen to pop up on All.
The second icon in the bottom navigation bar of the main view gets you to the list of your subscribed communities. In the searchbar at the top you can search for other communities over all instances.
Highlighting text is a pain. I've realized you can't tap or swipe the cursor to select more. You can only swipe over text and hope you got it all. This is still an alpha build in active development though.
The bugs I'm talking about are unmistakingly a backspace bug and a cursor bug. I would blame my phone then, but I've had it on different phones with different keyboard apps. Oh well, thankfully the webapp straight from an instance is great as well.
What keyboard app are you using? I do also hate that when editing a comment my cursor dwfuskts to the very beginning of the first line. Have it be after the existing txt makes more sense.