Achebee,
You really don't need much information to accomplish this. With the Premium Plus, you simply remove the five screws on the top of the box that retains the little access panel and pop that up with your fingernail or small flat screwdriver. The HDD drive bay is right there and the required cable should already be in place and in reach. With the power OFF, just plug the drive in, drop it into the bay and put the cover back on. Then turn the AZBox ON and it will recognize the drive during its boot-up sequence.
Prior to installation, you should consider formatting the HDD with your PC in FAT32 style. However, you can go into the menus and have the AZBox format it for you in LINUX ext2/3 style. I think that the HDD records and plays back better in LINUX than FAT32 (LINUX allows for larger block sizes). However, if you format in LINUX then you cannot easily pop the HDD out and connect it to a PC with Windows only OS. Not that there is a great need to do so, but in certain instances it can be quite handy. Say for instance you want to make a backup copy of the HDD. It goes a lot faster with a PC than with the AZBox. Of course, if your PC has LINUX OS, then you have no problems with letting the AZBox format it for you.
I have allowed the AZBox to format the HDD in LINUX, but sometimes wish I had tried it first in FAT32. No biggy. Use your own judgement.
A word of caution: Don't upgrade firmware while a HDD is installed and has a lot of files stored on it. Before you upgrade the firmware, power down and disconnect the HDD first. Then go about the upgrade. Plug it back in when finished.
RADAR