How to use the edit button.
If you wish to add something to your message, simply use the edit feature to modify the original post.
You will find the edit button at bottom right corner (see attachment No 1).
Push the button and a new window appears (see attachment No 2).
To edit your post or to add something, go to the part in the middle with the title:
Edit Post
After editing you should fill out the line named: Reason for Editing.
After this, push the grey button Save Changes and you are done.
You will be able to use the edit function ca. one hour.
Why you should use it?
Check this.