Click the blue "new post" button at the bottom right. Then drag a text box over to the dotted line area. You may now click and type in the text box. You can drag other elements over too.
You can choose to click post or save in the upper right. Drafts can be accessed from the bottom right button after you have saved your post. After publishing your post, you can still click on the post to make changes. Then click update.
Clicking the "down arrow" shows a menu so that ou may delete the post.