To make a comment, simply click on the comment icon at the bottom left of another user's post.
When you click on this comment button, it expands the thread so you can see others' comments before you make a comment.
Starting in early March 2025, we modified the reply flow so that there will only be 1 single thread instead of multiple comments layered on comments.
You can still reply to comments, but it will be just 1 single thread. This makes it easier to see all of the comments instead after clicking "load more"