Is there anything special needed to be done? I was going to put the motherboard on the anti-static bag, but does the bottom of the motherboard get very hot? Never tried this before. Anything I should be careful of?
You'll be fine, just make sure there's nothing underneath that might short out any connections. It won't get hot enough to melt anything. I had my system on my glass desk for a few weeks while I waited for my new case to be delivered.