On same IDE cable? drive 1 primary MASTER, drive 2 as Primary Slave. jumpers on the hdds. Make sure your BIOS is
set to Auto detect hdd.
after physically installed, (if windows doesn't automatically detect and add new hardware) get back in BIOS and see if BIOS detects the 2nd hdd. Windows may (or may not) show the hdd at 1st boot... may have to reboot with boot disk, fdisk, change active disk (to the 2nd hdd) and formatt.
and hopefully someone with more experience installing hdds will come help answer questions here for ya ! ;-)