Garageband and M-Audio Fast Track USB music interface

Hi All
I am totally new to OS X and just got my fist iMac (so very happy) even though I have worked with computers for about 20 years in different ways.

Now I also play some guitar...

So I bought myself a M-Audio Fast Track music interface.
And I installed its drivers and also the Pro Tools that came along.
but have some issues or questions...

First off..when I plug the music interface into the iMac via the usb cable it does not show up as a unit/disc image on my desktop or in finder as does all other usb hard drives and similar...Is it not supposed to?? or is something wrong??

Secondly, and this might very well being a fact of that Ive not understood correctly...
If I want to just plug in my guitar to the musical interface and then hear my guitar through the iMAC - how would I do that??

I assume I need to do it via Garageband but how exactly??

And in this case I dont nessiscarily want to record but simply play my guitar and hear it amplified through the musical interface and the iMac and also being able to use the different amplifiers present in garageband...

Now is that at all possible and if so how???

Or if I simply want to plug the guitar and play is there other software that does amplify and offers different amplifiers and effects in a simpler or better way than Garageband?? on an iMac...

I hope theres someone out ther that could help me out on this...
Best regards Micael From sweden...

Hi an thanks for your reply.
And NO I only see 2 entries there for 2 built in microphones...could that be it??
I have tried for example this:'
1) Launch GarageBand and go into the GarageBand menu.
2) Select Preferences and then AUDIO/MIDI
3) Set the input and output driver as the Fast Track USB
4) Close the Preferences and Create a New Music Project
5) Go to the Track menu and select New Track
6) Create a Real Instrument Track and the Track Info pane will open at the right side of the screen.
7) At the bottom of the Track Info pane click on Input Source and select MONO 1 (M-Audio Fast Track for the XLR Mic input and MONO 2 M-Audio Fast Track for the guitar input)
8) Turn Monitor ON
9) Click the record button in the transport and try recording.

and also tried it like this video exactly but no sound...
http://www.youtube.com/watch?v=dAU3XVAgVJ4

help please...
best regards micael

HI I now downloaded new driver from http://www.avid.com and I now can see my unit in audio/midi...and I hear sound...horray...

However I get a snapping sound in the speakers when playin my fender guitar...like small short firecracker sounds almost..hard to describe...
Anyone who knows how I can get rid of them??

And F many thansk you got me forward on this...
best regards micke

the sound i hear now I dont like is almost like when you listen to a really old very much played vinyl record...

anyone know what it could be??
guitar cable??