Hello,
To enable more than two simultaneous RDP sessions, you need to install the Remote Desktop Services role and purchase the appropriate number of RDS CALs.
First, you'll need to install the RDS role via Server Manager. This includes RD Licensing, RD Session Host, and RD Connection Broker roles. Since you have 5 CALs, if these are RDS CALs, you should be covered for 5 users/devices.
Once you have the RDS CALs, you need to install and activate your RD License Server through the Remote Desktop Licensing Manager and install the CALs. Then, you'll have to configure the RD Session Host to point to the RD License Server to ensure it recognizes the installed CALs.
Microsoft offer a 120-day grace period for RDS where you can install the RDS role without needing to immediately provide RDS CALs. This allows you to set up and test RDS functionality before committing to purchasing the CALs. You can add the RDS role through Server Manager. Then, go to the RD Licensing Manager, and the server will operate under a grace period allowing you to connect more than two users.
Here are some references:
License your RDS deployment with client access licenses (CALs) | Microsoft Learn
Activate the Remote Desktop Services license server | Microsoft Learn
I hope this helps.
Best regards