Just plug it in and turn it on.
The new HD is Serial ATA drive and it is always the master one.
Old one is IDE HD and can be set to slave (there is a jumper for that on the drive). Just don't plug the cable upside down.
Make sure that BIOS is set to auto. look for drives.
It will configure it self in this manor:
C will be primary partition of your SATA drive
D will be primary pertition of your IDE drive
E will be secondary prtition of your SATA drive etc.

Tip:

When you plug it in, remove the partitions on your IDE drive.
The reason is that your primary partition is so-called ACTIVE partition, and only way do "deactivate" it is to remove it. (System can boot only from active partition)
Wise people say that it is a bad omen to have 2 active partitions in one system.