Converting hella 500's to HID and then installing, got a few questions

ok, I'm sorry for questions that I could search and find answers to, but I'm a worry wart and would like answers specifically in response to my questions although they'll probably be the same.
Anyways, I finished my Satoshi grill last week (very happy with how it turned out) so I ordered some lights for it, I ordered some hella 500's, an HID kit and a switch from otrattw (I like that they have the same look as the stock switches) but since I've NEVER done car lighting before I'm confused by all of these wires and want to be sure what I'm doing. The Hella 500's come with the wiring harness and relay which has the following wires
Red: 12v+ from battery
Blue: Ground
Yellow: Trigger for Relay (so goes somewhere on my switch)
Black: output to lamps
and it also has a separate green wire which is power for switch 12v+ (so goes somewhere else on my switch)
and then the actual lights for the Hella's have the blue and black wires, black would be for power, blue for ground, but I'm swapping this out for my HID's (using this tutorial: youtube.com/watch?v=lZGjUcMpUHE) and the HID has a black and a red wire, this is where I'm confused, but I'm guessing that the red is the power and black is a ground? The only reason I ask is because I'm more familiar with AC electrical than I am with DC, I know NOTHING about DC and a little about AC. I've heard that HID's are supposed to use AC which is why they have a ballast so that's why I'm wondering if the black is a negative instead of ground (plus red and black are the terminal colors on the battery, maybe I'm just over analyzing though) but that's my first issue. Second issue is with the switch itself, it has 5 prongs which are numbered in the diagram that comes with the switch:
8: connect to a ground for the upper light
7: can be jumpered from #8 for the lower light negative
2: Connect from your source with the inline fuse
3: connect to your relay or acc.
6: normally connected to dash light circuit to be on when your dash lights are on.
So I'm assuming that the 8 and 7 can be tied in together and connected to a ground, 2 probably goes to a 12v power (I'm guessing that green wire), 3 probably goes to the yellow wire from the harness, I don't know what the hell 6 is.

So please help me out by telling me what 6 is on my switch/what do I put on it, and then tell me if the other things I've guessed are right or if they're wrong what do I do to make it all work, sorry for the questions but my friends brother in law was telling me he messed up wiring his and then they just flashed for a while and then went out, like an expensive light show, so I'm a bit cautious. Thanks anyone for the help.
Edit: Ok, sorry, my glaring lack of DC has become painful, I just found out that the negative on a car IS a ground,

 

double post to both bump and ask for confirmation:
ok, so I just went out now that it's day and I can go under my hood and mess around with stuff, the HID conversion went well, I just tested them by putting them directly to the battery, not wired or in line with the relay or switch. Then I went ahead and tried figuring out my switch, the top two (7 and 8) can be grounded together, the #2 tab is my upper bulb in the switch (lights up amber when the switch is in the on position) the 6 tab I was confused about lit up the green lower bulb in the switch (always on when the car is on) and the 3 pin is the only one left so by process of elimination that must go to the relay. So 7 and 8 are grounded, 2 will go to the a 12v fuse (with the green wire from the harness), 3 will be the yellow wire and then 6 will go to another 12v source. So my NEW question is, can I tie the 2 and 6 tabs in together and just run a new fuse to those? I don't want to run either directly to the battery or the light will always be on rather than just on when ignition is on, or so I think. Like I said I know NOTHING about DC electrical.