Plug in both, set one to master, one to slave, the master having your OS on it.

So I can have 2 plugged into one port

Yuppers, not a problem. You also have "cable select" as an option for "master/slave" on your HDD's, I forget if the plug at the end is the slave, obviously, it's one or the other, go figure. Been a while since I hooked 2 HDD's up in my system, I must be gettin old.

Most HDDs have the jumper settings printed on the top of the casing. Check those settings to determine where the jumpers need to be placed on both HDDs. If for some reason the HDDs do not have the jumper settings printed on them, you can look them up on the manufacturer's website.

I am pretty sure the end connector is the master and the next one down it slave but I know people who have hooked them up the other way and not had a problem (I think with newer hard drives, the on-board firmware doesn't really care which one it is and the jumpers are really an easy way for the relatively "simple" BIOS to figure out which one is Drive 1 and which one is Drive 2). And for the original poster, pretty much all IDE ports are 1 connector but 2 channel meaning you can have two IDE devices plugged into one port. This is why a lot of computers have the CD/DVD drive on the slave connector and the hard drive with the OS on the master connector.

Yeah I installed it using the second one down and all works fine!!