HERE if you need to know where to buy it) as trying to follow all this without actually doing it step-by-step with the materials in hand is indeed "confusing" as you put it and really a waste of time.
Once you get the Swap Magic discs, some more detailed guides outlined step-by-step are available here though:
PS3 USBLD Loader Tutorial for 60GB and 20GB with Videos
How to Play PS2 iSOs on PS3 via USBAdvance (20/60GB NTSC/JAP)
How to Play PS2 iSOs on PS3 via USBAdvance (for PAL Systems ONLY)
If you follow those guides and read through their threads while doing so you should have no issues.
Yea, unfortunately if you don't have it yet I'd buy it first (see