mastodon doesn't have communities/magazines like instances on the threadiverse do. instead, they categorize things by individual users, and allow people to search via hashtags. here on kbin, mastodon posts are pulled into our magazines and we have a dedicated "microblog" section for them.
Mastodon users replying to threads will show up like other comments/posts do.
Basically: you follow mastodon users not mastodon communities (which don't exist)
Edit: I should also mention that you can pull up a user's profile the same way you do for a community (just with the user profile url format instead)