The best way to get started on Mastodon as a brand new account is:

1) Find a friend who's already here. It's not that hard. Use search. If they're not here yet, find a different friend. You're bound to find someone. Follow them.

2) Look at who they are following and who is following them. Chances are you will see familiar names, and other interesting accounts. Follow them too.

3) Check out some of the people you just followed. Repeat step 2. Do this a few more times until you are following a few dozen accounts.

4) There's a good chance that by now, some of those people are following you back. Look at your timeline, engage, reply, boost what you see.

Over time you will have a following and you will find more people to follow.

Yes, it takes some effort to get established in a new place. It's NO DIFFERENT on Birdsite. Birdsite does throw random content at you, but when you're just starting out it's TRULY random content, and you will still have to seek out people you actually want to follow and engage with. This is no different, and is in fact EASIER because you already know people and can look for them.

By the way, I highly recommend that you leave your following and followers lists open so that people can use them to find other people. Mastodon lets you hide them, but don't, unless it becomes a problem. I've seen far less judgmental "You are following this horrible person so I will block you" bullshit here.