I downloaded the official Datasheet for the chip and was reading it yesterday. Have to say, I don't like the idea of it having a built-in amplifier with no way to bypass it. Wouldn't the levels need to be taken down before connecting it to something like, say, a multitrack recorder input?
Having an amplified output would mean it's way above line-level, wouldn't it?
Still learning this stuff but I can imagine the distortion would be insane!
It's a lot better to have an amplified output than a too low output. The signal out will be about 5 volts at max output, while a line output is around 1 volts and if you feed a signal that peaks at 5 volts into a line in, then you would most likely end up with a lot of distortion/clipping. However this is very easy to fix with some resistors/potentiometers.
In some cases an amplified output that is too loud is very beneficial, like for instance if you want it to go through a passive EQ circuit. A passive EQ circuit is pretty easy to create, but it requires a louder signal than an active EQ circuit (which basically is a preamp or several preamps and a passive EQ circuit). An EQ circuit is basically just some potentiometers and some capacitors.
If you are going to use the signal to feed several line inputs it will also be beneficial, in basic you only need to add a potentiometer to each input.
Think of the potentiometer as a mixing device, it's got line in, which is the middle taper that moves across the graphite (the middle pin of the potentiometer). It's got a line out, which goes to the line in of whatever you are feeding the signal into. It can be on either side, it's up to you, but the usual way would be to turn up the volume clockwise. The last pin goes to ground. If you look at the potentiometer from the top, pins facing upwards, it would be pin left to ground, middle pin is line in and the right one is the line out. You could also swap the line in and line out, it doesn't really matter. Find the way you like and stick with it, it's easy to solder the wrong way and you realize just when everything is screwed together.
You might need an extra resistor to prevent it from going too loud, but that depends on what you have in the other end. It could be wise to use a trimpot, maybe 50K and preferably multiturn pots so you can finetune it easily at any time from 0 to 50K which should be enough. this one shold not be connected to ground, as that is the first potentiometers job. If you use a small value on the potentiometer it will act as a filter and remove higher frequencies, so it might be wise to use higher value potentiometers such as 500K. Preferably it should be a A500K which has a logarithmic curve. If signal has zero resistance to ground, then it's completely lost and should in theory be completely silent.