Right now, using liftoff app, I have to open 2 tabs in a browser. Find the community on one instance, let's say !abc@lemmy.world, and actually log into my instance on the second tab. Then search that !abc@lemmy.world in the second, logged in, tab. I can then subscribe.

Am I missing a much simpler way of subscribing?

I have been using https://browse.feddit.de/ to find communities. I can't subscribe directly from them when clicking a link from that site.