Essential Business Server (EBS) enforces client licensing in a fairly strict manner, its important to understand repercussions of being out of compliance in order to ensure that your clients’re able to successfully connect to network.

How to Properly License Clients

Assigning CALs to users’s a simple process:

1. Activate server. Do this from Control Panel\System as you would for any Windows Server.
2. Install CAL Packs using EBS Administration Console.
   1. Open EBS Administration Console and select Licenses tab.
   2. Select Install CAL packs from License Management Tasks.
   3. Follow prompts, and enter CAL Pack product keys when prompted
3. Assign CALs to users or devices using EBS Administration Console.
   1. For existing users, open EBS Administration Console and select Users and Groups tab.
   2. Select user and double-click or choose Change user account properties.
   3. Select CAL tab and assign appropriate CAL (Standard or Enterprise).
   4. Click OK to exit.

Full Article: EBS blog