The Marshall MG30DFX is split up into two separate channels. The first is a clean channel that consists of parameters for volume, bass, and treble. The second is an overdrive channel that has knobs for gain, bass, treble, contour, and volume. There's a button the amp to switch between the two channels, but you can also control this with a foot switch. Lastly, the effects section has a knob for choosing between the four different types of effects (reverb, delay, chorus, flanger), and another knob for setting the amount of the effect you'd like. The amp isn't difficult to use, so I wouldn't think that you'd need a manual.
The sounds heard from the Marshall MG30DFX is just a bit above average in my opinion. The clean channels is just and crunchy in the sense that it almost sounds like it's compressed a little bit, while the overdrive channel is a bona fide Marshall distortion. The distortion is definitely where this amp makes it's money, but the clean sounds good enough to fall in line with it as well. The effects aren't the best at all, especially the modulation ones, but the reverb is decent enough for sure. It's nice that you can get a number of different sounds all in one place between the two channels and the effects...
The Marshall MG30DFX is a great amp for a beginning guitar player who wants something better than a simple speaker. This will give you options to mess around with and to get yourself started with. The amp is even fine for more experienced players who want a practice amp that's a bit more in depth. Personally I wouldn't use this for recording, but I've used it for a few shows a while back. A friend of friend left this amp at my friend's house for a few months so we ended up using it for practicing and a few shows, although I wouldn't use it for a show now. The Marshall MG30DFX is a fine practice amp for the money, and is a great way to go if you're looking for the Marshall sound in a compact device.