Navigate to your Profiles tab and click the plus sign under Available Payloads.
Make sure iOS is your platform and select WiFi from payload type.
From here give your payload a name, set the SSID under Service set identifier, select if you want to auto join the network, select if the network is hidden, select your security type and if you are using a proxy.
For Enterprise security types:
Under the Protocols tab you will select the authentication protocols and Inner Identity protocol types for TTLS.
Authentication tab is where you provide your login and password information, Identity Certificate and Outer Identity for TTLS, PEOP and EAP-FAST.
Under the Trust tab any certificates or certificate names can be added for authentication purposes.
Back under the main WiFi payload screen you can set your Proxy.
Automatic allows you to simply specify your proxy server
Manual requires the server and port, as well as the username and password.
Your payload will now be available for selection when creating or editing a Smart Device Profile.