Most things you find on Provision OS will work on AOS-S (ArubaOS switches) as what was named Provision OS till the 15.x release is called ArubaOS starting with the 16.x release.
You can get product documentation from the Network Information Library: http://h17007.www1.hpe.com/us/en/networking/library/index.aspx?cat=switches&subcat=aruba_3810
.. where the HPE ArubaOS-Switch Access Security Guide will give you probably the needed information on assigning VLAN (but also dynamic ACLs, and other features) via RADIUS.
As Tim mentioned, the 'default' method with IETF attributes (Tunnel-Type, Tunnel-Medium-Type, and Tunnel-Private-Group-ID) will work and is what most people will use. With the RFC4675 attributes Egress-VLANID or Egress-VLAN-Name you can even assign tagged VLANs in addition to the untagged VLAN.