You may edit your previous posts by going to your account summary, which can be accessed by clicking on your profile picture in top right corner on any of the pages.
You can see My Articles, My Events, My Meetups, etc on this page. If you wish to edit an article, you may click on My Articles and you will be taken to My Articles Page. There is a small EDIT icon in the top right corner of your posts. Click on it to go to edit page and edit your post.
Similarly you may click on My Events, My meetups, etc on account summary page to go to the respective pages and edit your posts.
Please note that you can not yet delete your posts.
atghelp.wordpress.com 