One helpful point (if you do not already know it). ...

After you click the "Pencil (Create a post)" icon, and BEFORE you insert any text or images into your post-to-be, you will see the word "EDITOR", at the top-right corner of the "Write your story ..." box.

Click on that word "EDITOR," and it will activate a small menu of several icons that you can use to format your post.

(If you do not click "Editor," and start inserting text or anything else in the "Write your story" box, the option to choose "Editor" will disappear. Strange, but true.

Best of luck!