What are the benefits for be promoted to level 3.
At the moment, nothing, other than when everything is running normally, posters at different levels may have a different number fo stars beside their username.
As you can probably guess, the new forum software allows for the different levels to grant different permissions. For example, a poster at the lowest level (less than say, 50 posts) may not be able to post links and images, or may be useful in future for (for example) allowing a poster to read feedback but not post in it until they have reached 3 months on the site and 100 posts. It will be something more finely tuned in future, but for now at least, I don't believe there are any differences from a. user point of view.
Rich Text Editor.
To edit a paragraph's style, hit tab to get to the paragraph menu. From there you will be able to pick one style. Nothing defaults to paragraph.
An inline formatting menu will show up when you select text. Hit tab to get into that menu.
Some elements, such as rich link embeds, images, loading indicators, and error messages may get inserted into the editor. You may navigate to these using the arrow keys inside of the editor and delete them with the delete or backspace key.