I'm new to playing the electric guitar and how amps work. But my amp is very basic and only has voices (warm, crunchy, OO 1, etc..) gain, volume, and equalizer. It also had effects labeled "Rev", "DLY", and "Mod". So I would just like to know what I should set up so I have a nice rock sound.
The best answer is just to play around, but here are some general tips:
Gain Setting the gain control sets the level of the preamp, and when the final volume is set fairly low this can set the amount of distortion in your tone.
Rev is likely to be reverb, which is a sort of echo effect. Turning this up will make it sound like you are playing in a large stone cathedral, while turning it down sounds more like a soft-walled studio.
DLY is probably going to be delay, Delay is kind of similar to reverb, but ultimately different. Delay repeats the end of the sound as an echo, and continues to repeat it, slowly fading away. You can adjust the delay time to form some cool sounds. A long delay with sound like your classic 'echo' with the sound repeating and fading away.
Mod is likely to be modulation. If you look on your amp, there might be two separate gain controls for 'channel 1' and 'channel 2'. modulation controls how quickly or slowly the sound modulates between these two channels. This can create a sort of distortion where you modulate between high gain and low gain.
For a rock sound, i would go for a lower reverb, and turn up the gain a little. Add modulation to your own taste, and season with some delay if you want (personally, i rarely use delay). For a more metal sound, throw in more gain and hit the modulation.
I'm not sure, if what you call voices are digital presets, that change the settings of the other controls or base tones that are modified by the other controls. TBH, your amp doesn't sound all that basic - I had one that just had a volume knob on it. Regardless of how voice works, I'll try to explain what the knobs control.
As Eddie Van Halen once said "volume is tone", so you've kind of got to balance your gain and volume knobs for a given level of volume. If you want the most overdriven sound possible, turn the gain to max and the volume to how loud you want it. For an ultra clean tone, turn the gain to zero. However, you're probably going to want to find sounds in-between these extremes. With maximum gain, the sound will work well for single note lines and power chords and your notes will sustain longer, but will sound murky and undefined when you play fully voiced chords. Minimum gain will give you an ultra-clean tone, even when you're going for a clean tone, a bit of gain can add warmth and character, if you keep it below the level where it starts to get a bit crunchy. A crunchy tone would be somewhere in the middle that lets you just get away with playing full chords without it being too muddy sounding. Don't forget you can use your guitar volume knob to lower the volume, this has can have an effect similar (not exactly the same) to lowering the gain allowing you to switch between a full gain lead sound and a crunchy rhythm sound on the fly.
There's no right way or wrong way to set the equalizer, but if you are playing along with others or to a backing track, you should try to adjust it to get the best overall blend with the rest of the music. In other words, try to find the space in the sonic spectrum where the guitar fills the sound, but without interfering with the bass or vocals.
Reverb and delay are similar, in that they add repetition to a note. Reverb is like the sound in a cathedral in that the note takes time to fade out even after you've stopped playing, delay is a distinct echo. These effects add ambiance, but if they are used too heavily can drown the sound as new notes don't stand out clearly from the old ones still reverberating. The tempo of the song is often a good guide to how much reverb you can use. The slower the tempo, the more reverb you can get away with.
Modulation is a catch all for various effects like flanger and tremelo. Without knowing more about your amp, I can't really say what this knob does exactly, except that modulation effects are usually best used subtly or in short bursts and you needn't concern yourself with making them part of your everyday sound.
Experiment away to come up with a sound you like and try to analyse the sounds you hear other people play. Good luck!