Can't sleep, spreadsheets will eat me

I know that some of you know and love your spreadsheets, but mine are sprawling and large and numerous and I don't know how to make them do what I want.

I will be getting Excel training soon, but that doesn't help me now so I thought I'd ask you guys, since you're a clever bunch.

I need to run a mail merge. I have a spreadsheet of dealer addresses, and I have a list of people who are attending my event. I am trying to find a way of getting information from each spreadsheet together (delegate details from one and address details from the other) so I can run a mail merge from one document. I know that you can do data pickups, but I don't know how, and I don't know what the parameters are in terms of what I can and can't make it do.

Please help!