This platform does not yet have subreddits as you're used to from Reddit, but we can work around it.
First, get started as described in this post.
Then, make your own space - does not matter what you call it, it's up to you. If you'll be posting WSB stuff, call it wsb-username.
Then, tag every post you write about wallstreetbets or WSB with wallstreetbets and WSB, like I did this one. If you now click one of these tags (see bottom of post), you will be taken to all the posts that are also tagged with these tags, which functions as kind of a makeshift "subreddit".
The UI will improve soon to streamline this, sorry about the hurdles.
Anyway, really happy that 2021 is starting with the destruction of monetized shadenfreude (funds that short), keep it up fellow degens!
P.S. No I'm not on the team, just a user and enthusiast.