Write is to input information, Read is to read it. Those are pretty self-explanatory. I just use those options and step-input.
As for touch and latch, I may be wrong as I don't use them but I think touch overwrites whatever you have 'written', and latch amends what you've 'written' without erasing anything you haven't moved.
That's not very well explained, sorry!
Touch usally means if you arm the volume with touch,As you adjust your volume fader it will write a corisponding envelope.When released it returns to zero.
Latch is pretty much the same but when released it"latches"at where you last touched the fader and bulldoze straight ahed.
