So but I can’t figure out how to edit my post. Can someone tell me
It seems that you can only edit your post when it is the last one…
You can only edit your posts within 20 minutes of posting. If that time has passed, you can simply make another post and title it as a revision (or correction or elaboration, … whatever) of the earlier post.
Within the 20-minute window, just click on the “edit” option located on the lower right of the post. You will then get a screen with the post and you can make your changes.