The idea is straightforward, particularly if opening the computer doesn't worry you.
Assuming you are using XP and have a spare PCI slot on the motherboard.....
Open the box, remove a blank from the back of the case opposite where you will place the new card.
Plug the card carefully and fully home with its 6 ports accessible at the back of the computer.
Close the computer and enjoy!
If you don't understand any part of this, tell us what you want to know and say what version of Windows you are using.