Hi Monroy,
You can only assign a user to one level, but you can set pages and restricted content to be available to multiple user levels using the minimum and maximum level settings. This means that you could make it so that a user has access to multiple different levels of restricted content.
We created a video explaining how to set restricted content, which you can watch here: https://www.youtube.com/watch?v=7itl4aP1uZY. (The part about the [restricted] shortcode is closer to the end of the video.)
Also, from our FAQ:
How do I restrict content based on the privilege levels?
To restrict content to a certain level(X) your shortcode would be: [restricted level=’X’]…content[/restricted] For all levels above “X” level: [restricted minimum_level=’X’]…content[/restricted] For all levels below “X” level: [restricted maximum_level=’X’]…content[/restricted]
