Mac just arrived - need help with USB HD

[Moria]

OK, my new Mac Mini's just arrived. I've got it set up and running alright. But I've downloaded some software for it already onto my USB hard drive. But when I plug it in it comes up with a screen saying
"You have inserted a disk containing no volumes that Mac OS X cn read. To continue with the disk inserted, click Ignore"

So I went to ignore the first time, nothing noticible happened, so I went to Initiiaze and it came up with a screen with "First Aid" and some other things.

How can I just see my files and copy them over to this computer?

Thanks

 

[robbieduncan]

We need to know what format the partion(s) on the drive are in.

 

[Moria]

Doesn't matter anymore, I copied the files onto my bro's iPod and then copied them over to the Mac.