First off, nice case pick. The Antec 1200 is HUGE, and from what I've seen, pretty easy to install hardware into.
So to move the deal with the "surgery," there's a couple of rules to follow. Though I'm sure some people will say you can not worry about it, or need to follow another rule, so I'll try to give you some basic, safety tips.
1) Don't Disassemble or Reassemble wearing socks while on carpet. Why? Static Electricity? Shock the motherboard can mean fried motherboard. Remember that.
2) Wear latex/rubber gloves. Reduces the chances of shocking the system. (Though I have to admit, I've bare handed the installation before)
3) Work on a flat surface that doesn't conduct electricity.
4) Have a safe anti-static surface or cover to rest computer parts on. If you bought your motherboard, it's typically covered in an anti-static bag for safety. I reuse them to rest my mobo when it's not installed.
5) A PC Installation kit does help; has a variety of different screwdrivers for you to use, and the one I used had a nice tool for dropped screws that are in hard to reach.
Those are some basic tips when installing PC components. There are others, and a few can be ignored, but those are some good basics to follow.
Now, remember when you're uninstalling the hardware, you first turn off the PC, then turn off the PSU so there's no active current running. Once done, press the power button to release any stored power, then unplug the PC fully, and you're ready to start.
For a trained person, you can move the PC hardware from one case to the other in under an hour, but I give it a fully hour or so for a first time job, since you want to be careful not to damage anything while moving the parts. The first thing I installed in my PC was the PSU because of it's location, but in the Antec, I believe you want to install the motherboard first w/ the CPU and heatsink already on. Be sure to remove both side panels to make sure everything's the way you need it (as well as better hide cables for better cable management and airflow). Good luck!
