First off congrats on your spindle kit purchase.
It's hard for me to recommend a good beginner site simply because there are so many out there. Some are simple and basic, some are more informational, and everyone's different. Some people need alot of info, and others just want the gist of things so they can figure out the rest. You don't want instructions that are too vague, but on the other hand neither do you want ones that throw way too much info at you.
The above video is very helpful, especially because it deals with a low whorl spindle.
You might also want to look at http://ispindle.com since it focuses on drop spindle spinning.
If your whorl (the disk) is on the bottom, with the side with the hook being the top, then yes you have a low whorl spindle. You spin it the same way as a high whorl spindle: wind on, secure the yarn, twist it, draft yarn, repeat, except that the yarn on a low whorl spindle has to be spiraled up the shaft before being hooked on.
The joy of spinning site has two videos depicting spinning on a low whorl spindle
As for fiber preparation: If you have roving (a rope of wool) all you have to do is tear a chunk off, predraft and start spinning. to predraft, hold your hands a few inches apart then gently tug the roving open moving across the length of the roving. If it's not budging, position your hands farther away. There are videos of predrafting at ispindle.com Theoretically, you can spin from the roving without either predrafting, or tearing strips off, but I find it easier to just spin from a small piece of roving and join a new piece every once in a while than spinning from a giant length, and most commercial roving gets too compressed to spin evenly from without predrafting.
EDIT: This article from Interweave Press' spinoff magazine may be helpful (pdf file): http://interweave.com/spin/spinoff_magazine/files/sum_05/Spin_Basic%20sum05.pdf