The numbers on the electrical relay?

I just bought some lightforce spotties today and as I am not very electrically minded I thought I would run afew questions passed those of you who are.

1. What do each of the numbers on the relay I bought today relate to? and is it neccessary to run it through relay, why?

2. The numbers and diagrams don't make a lot of sense to me but they are 85, 86, 87, 87a, and 30. I am mounting a switch in the car and it just a simple three point one that is ether on or off. The numbers on it are 1, 2,3. 1 goes to the relay (but where?) 2 goes to batery and three is ground.

3. On all of the (grounds or are they negatives?) needed when wiring spoties (one from each light, one from the switch, and one from the relay (I think) can they all be put to the same ground? and where is a good place to put it on the car.

4. I have some 30 amp wire will this be sufficient for the job? Also when connecting both the lights together do they go to the same connector on the relay or seperate ones. If they go together can I just use one of those male/female conectors and slot them both together at the relay.

It is something which I feel I should be able to do myself and I did put some spotties on another car 10 years ago but didn't use a relay they worked fine but I would rather do it properly this time.

What alse should I look out for when fiddling around? If it is all too hard I might make a trip to my auto sparky tommorrow, just depends on my patience I guess.

cheers in advance,

Charlie