How to assign Enterprise or Functional Licenses to users

Hello experts,

I'm actually new to AX 2012, so please allow me to ask basic questions.

I have been researching how to apply Enterprise or Functional User Licenses to each user, but I cannot find a window that allows me to assign named user licenses to each user. In User window (System Admin > Common > Users) it is possible to assign Roles (such as Sales Manager or Sales Clerk) to each user. I understand the Roles are associated with the license types, but the question rose-- how can AX 2012 recognize a license type for each user?

For example, Sales Manager Role requires Enterprise User License. Is it possible to assign Functional User License and Sales Manager Role for the user?

The TechNet seems not having an article for my question. Would anyone give me a guide?

Thank you for your help!