You should have the ip-pool on the router that is offering internet to your users (i.e. hotspot/pppoe or the like).
Sounds like you have a second machine used as authentication server using the UserManager package?
If you want, I’d probably be available on the phone today for some more hours
yeah the ip-pool is a name related to the mikrotik definion for ip-pools on the mikrok or radius/mysql server using that definition, if i remember right.