toronado455 wrote:

I need the mixer in order to create a
small mix of instruments that will be sent to the inputs of the
computer soundcard. That part I'm pretty sure I understand how to do.
But I also need to be able to monitor the output of the soundcard
itself, seperate from the mix that is being sent into the soundcard.
Can I do both these tasks with the same mixer?

You can, with many mixers, but understand that your real mixing will be
done in your computer. Ethan Winer has an article on his web page about
setting up a small mixer with a simple sound card so that you can hear
what you're doing.
http://www.ethanwiner.com/mixer2daw.html

There are other ways of doing it, and there are other approaches that
don't use a mixer, and there are "sound cards" that provide this
function and are intended to use without a mixer if you're recording
just one part at a time.

One of these days, Mackie will get around to publishing the ultimate
mixer reference that I wrote for them a few years back. Until then,
you'll have to scramble, buy a few wrong things, work around your
problems, and learn how signals get from an input to an output and what
happens in between. That's what it's all about, and you CAN learn that
sort of thing with a small and inexpensive mixer. But don't buy too
small.