The cool thing about guitar amps is that you can mess with the knobs until you find the sound that you like. There is no particular way to use it, just try to find a tone that suits you. Start with gain controls down and tone knobs at 12o'clock. Turn up the gain(one at a time) to get distortion and more sustain to your sound. Turn the distortion up midrange down and treble up for metal sounds, more bass and midrange for bluesy sounds. just play around with it and you will see what I mean. Here
is a guide from Fender on how to setup your guitar. If you are not sure, a good guitar tech can make any old axe feel and sound great with a good setup
unfortunately, Fender do not have an electronic copy of your owners manual to download, but you can buy one for $5 direct from them here It is only a 1 page manual.... so you will get more from just messing with it.
Musicians spend there whole lives tuning and tweaking knobs to get the sound they are looking for. It wont take you long to start doing the same.:)