Unable to add Resources to Crew-related tab missing.

I am trying to add resources to my crew and I donot see the 'Related' tab under which you can add the resources.see here:(https://docs.microsoft.com/en-us/dynamics365/customer-engagement/common-scheduler/resource-crews)
Is it mandatory to have Universal Resource Scheduling license in order to add resources to a crew? I can't also see the Pools option in the type of resources. Could this also be due to not having Universal Resource Scheduling license ? I am still learning Dynamics 365. Could someone also tell me the difference between Resource Scheduling and Universal Resource scheduling?