We have SQL server 2017 in production environment with enterprise core license. Due to server load, we decided to use separate sql server for month end reporting, play environment, schedule reporting. We have one server which does all automated reporting using scheduler. A crystral report user who will be connecting to this server. Two users who will be accessing server for stocktake. Occasionally 2-3 users login to play environment for training. Three users will be accessing SQL server through SQL Management Studio from their PC. So in this case we decided to go for SQL Server Standard licence with CALs option, but don't know how many users and devices cals we need.