In fact, cases where it is necessary to connect 2 hard disks, boil down to two possibilities:
• one disc is already up and running, you need to install additional;

• there are no computer storage media, it is necessary to connect 2 hard drives.
Since the first case flows logically from the second, consider a situation when you need to connect 2 hard drives in the system unit. Power off the computer. Put it on a flat surface and remove the cover to access the motherboard.
Choose which hard drives will be the main, that is active to boot the operating system. Define a sequence by setting small jumpers-jumpers in the appropriate position in accordance with the diagrams shown directly on each hard drive.
Some differences between drives can be caused by interface hard drives. Interface can two ATA or SATA. With this you can connect 2 ATA disk on one cable, but the SATA drives are connected each with a single cable going to the motherboard. Hard drive with SATA interface due to interface connections do not require any additional changes to the settings of jumpers when connecting to the controller, to position master/slave IDE drives from ATA.
When you've dealt with the ribbon cable and interface, as well as prioritize downloads using the jumpers, install the hard disks into specially designed slots in the system unit. Connect 2 hard drives cables to the motherboard, and wire the voltage coming from the power supply.
Turn on the computer and enter BIOS setup. If the hard disks are not automatically detected, make their manual identification of the appropriate team. Then save the changes and exit the BIOS.