@sam so it's a bit janky, but you can post to Lemmy communities by mentioning them and formatting your post so it shows up correctly.
The first line is the title
The next lines are the body. I recommend mentioning the community and adding tags at the end so it doesn't get in the way.
To interact with Lemmy posts, you can follow the community, then all posts and comments will get boosted to your timeline. Posts only show up as a link, but you can open the link and read the post, then come back to mastodon to comment or interact with it. Remember to mention the community in your reply or it won't show up in the thread on Lemmy.
Hope this helps.🫡