The Enhanced Licensing will list different levels of Licenses, such as "Admin", "Super", "Standard", and/or "Read Only". If there are License Levels listed on your Contract, then your organization has purchased the Enhanced Licensing model.
The Legacy Licensing will simply list the number of Licenses that have been purchased, with no License Levels listed.
If your organization has purchased Named Licenses, then this means that only 1 Employee can be set to "Active" (allowed to log-in) for each License purchased. This is a 1:1 match for Employees to Licenses purchased.
If your organization has purchased Concurrent user licenses, then this means that you can have as many Employees set to "Active" (allowed to log-in) as you would like, but only the number of Licenses purchased can be logged in to the application at one time.