you can only hot swap with SATA or SCSI, IDE hotswap is not supported. External is inferior, its much, much slower and far more prone to error from normal use. If you get one of these xyzGB boxes, they are usually cheap stock hard drives too.
There's not really anything to guide about. You plug it in, and then you pull the lever and put a hard drive in and then close the door.
Issues that can prevent internal hotswap:
* A crappy chipset that doesn't support hotswap
* An inability to use a screw driver
* erm... that's all i can think of.
I'm not quite sure what you'd need a guide for, its just like installing any other device in your pc. You take the side off, you slide it in, you screw it in, then you plug it in. Hotswap bays just go where your cd-drves go instead of the hdd caddy. where you'd usually put a hard drive.
You don't have to have a hot swap bay if you don't want, just makes it easier so you don't have to keep taking off the side and screwing/unscrewing hard drives. Essentially, to make a drive hot swap with a chipset that supports is, you go into device manager and you go to your hard drive and you check the buttons. Under you hard drives, go to the hard drive and click "Optimize for quick removal" under "Policies", and for your ide, under the channel you can uncheck the two cachine options/
To remove a drive, you'd do it just like any other hardware in windows by clicking safely remove hardware. In linux you can just use mount /dev/sata0 (or whatever the device is) and umount /dev/sata0 (or whatever the device is, giving it a name). If you use windows and linux, you can format with the ext3 fileformat and use XP drivers for that, that will mean you don't have to faff with ntfs linux drivers.
There's very little need for a guide over something that simple. If you mean you don't know how to attach a hard drive, its exactly how you would fit a CD-Rom drive, if you google there'll be some newbie guides for install hard drives/DVDrom drives/ etc.
btw, there's something called eSATA now with is an external SATA interface which is neat, but i would rather have a bay in my case rather than extra boxes lying all over my desktop.