Hello,
advanced security is required, which you have installed, so you are good to go. You get 10 free users, for anything else, you need to install the Advanced Integration Module (scroll to Table 3 of the document below):
Table 3. Number of Concurrent SSL VPN Users Supported per Platform
http://www.cisco.com/c/en/us/products/collateral/security/ios-sslvpn/product_data_sheet0900aecd80405e25.html
For configuration of the SSL VPNs on an IOS router, see the document below, it is pretty comprehensive. You can either use CCP, or the command line for configuration:
AnyConnect VPN (SSL) Client on IOS Router with CCP Configuration Example
http://www.cisco.com/c/en/us/support/docs/routers/3800-series-integrated-services-routers/110608-ssl-ios-00.html