The selector knob allows you to use the bridge, neck or both pickups at once, the middle position selects both. In general, neck pickups are less trebly, more bassy and lower output than bridge pickups. Using the middle position effectively mixes the sound you get.

The volume knob changes the amount of signal that goes to the amp. Turning it should result (shockingly) in a less loud sound. However, if you are using a good valve amp, turning the guitar down results in a quieter AND cleaner sound. On my amps, I can turn the amp from loads of overdrive to completely clean with just the volume knob on the guitar. Your guitar has two of them, one for each pickup. You can therefore use the selector switch like you would use a distortion pedal. Neck pickup volume on 2-3, bridge pickup on 10, switch to neck for clean, switch to bridge for drive. Also, the volume knob allows you to go from anything between clean and dirty in this way.

The tone knob controls how much treble is cut from the sound. On 10 nothing is cut and on 0 a lot is cut. Some famous guitar sounds were made with a Les Paul with the tone control on 0. Slash and Eric Clapton used this a lot for what Eric Clapton called "Woman Tone". Neck pickup, tone on 0 amp turned to overdrive. Use this knob to lessen the treble while the other guitar player is playing their solo. Yes, amazingly some people actually keep playing REALLY loudly while the other one is soloing >

Most people never touch their guitars' controls and therefore need lots of pedals and things to make different sounds. Start your journey to become a guitar master by learning to use them now ?

Most important, play around with them and see what you can come up with. Electric guitars are more than just input devices. They're not binary on and off, you can control them in all kinds of subtle ways.