Hi Andy
Anyconnect licensing is a little complicated, but 99% of the time you only need the "Essentials" AnyConnect license for your ASAs. This gives you everything that you have using the old Cisco VPN Client.
Essentials is licensed per ASA, and not per user like the other ASA AnyConnect licenses.
AnyConnect Premium gives you all that Essentials give you plus "clientless" VPN (Web portal type stuff).
Configuration wize - it's pretty simple and similar to how you configure the old VPN support. There's a wizard to assist you in configuring it if you like that kind of thing.
HTH
Barry Hesk
Intrinsic Network Solutions