First of all, welcome! Here's some tips I found to be helpful.

1. Browse by 'all' to find new communities. If you find a post you like there, check out the community and subscribe to it. It's worth taking a look first to see how active it is too.

2. Once you have subscribed to some communities, I find your homepage is a better experience for every day browsing, since it's catered to you. Try sorting by 'hot' to get newer posts. Toward the end of the day, I like switching to 'top today'.

3. Don't expect the fediverse to be the perfect Reddit replacement. Not as many people use it, and there are unfortunately fewer niche communities than there are subreddits. That said, it's really what you make it. If you decide to stick around, make an effort to post yourself. It's something I'm still working on myself, but every bit helps!

I actually prefer Lemmy to Reddit now, because it's bloated with less bullshit, and I find the people (outside of a few communities) to be far more open-minded and less confrontational. Anyway, I hope you like it here!