Attaching Motherboard to Tray.

Hi: Very newbie question. I just bought a Coolermaster Wave Master to
put together my first system from scratch. Though I have built from
barebone systems before, I have never installed a motherboard, in this
case a Soyo Dragon 600 Platinum Ultra. I find the instructions about
installing the risers and bolting the motherboard to the motherboard
tray undecipherable. So:

1. In the bag of screws that came with the case, which screws are the
risers, if any? Would they be the six-sided (hex?) screws whose heads
are about a half-inch high?

2. If these are the risers, shouldn't there also be screws that are
longer than the risers that will reach from the top or front of the
motherboard into the tray?

3. Also, I've read somewhere that these risers should be made of brass
or plastic. Is this true?

Thanks.