Hello William D'Mello,
Thank you for posting in the Microsoft Community Forums.
If you purchase 5 Device CALs for Windows Server 2016, you can have up to 5 concurrent RDP sessions on your server. However, please note that you will also need to ensure that your server is properly configured to allow multiple RDP sessions.
You need to have a Session Host server role and an RD License Server role, and according to the license usage rules, the version requirements are as follows: Remote Desktop License server ≥ CALs ≥ Session Host Server. After installing and activating the CALs you purchased, you can have up to 5 concurrent sessions.
Hope the above information is helpful to you.
If you have any concerns, please feel free to let me know.
Best Regards,
Bblythe Xiao