I couldn't find a user manual, but here is what I could find; screenshots of the interface for the Sagemcom F@st 5355, which I believe is the replacement for the TG799 - http://setuprouter.com/router/sagemcom/fast-5355-telstra/screenshots.htm
As you can see, it's very similar to what I imagine you're probably used to. Just a word of advice - don't expect a huge improvement - you'll be disappointed.