I know it may be a lot of users’ first time using something that is decentralized like this. As I’ve been a Fediverse user for some time, I had been waiting for a big migration like this to happen as it usually happens with Twitter every now and again. Welcome to Fedi, hope you enjoy your stay!
I do highly recommend Mastodon! It is a great Twitter alternative, and is way more laid back at least in my experience. I use it as my frontend to the Fediverse on my phone as it is easier that way, but I prefer Pleroma and Soapbox otherwise. Still need a Lemmy frontend on my phone but, eh, not a phone user that much anyways.
I just spent the last hour looking at different Android apps for Lemmy and decided on Connect for Lemmy for now.
https://play.google.com/store/apps/details?id=com.kuroneko.lemmy_connect