There is many ways you can assisgn an IP Address to Client/Subscribers
1. You can return a Framed IPAddr from Radius.
2. Or You can you create a IP POOL locally as follows:
set access address-assignment pool TEST family inet network x.x.x.x/8
set access address-assignment pool TEST family inet range A low x.x.x.x
set access address-assignment pool TEST family inet range A high x.x.x.x
3. You can also define multiple IP local Pools and return framed-ip-pool VSA from radius to use a specfic pool for specfic subscriber(s).