The sound card is located on your motherboard, in a PCI slot. Uninstall the old drivers before you start. Shut the computer down, open one of the side panels up, and gently wiggly sound card out, side to side. It will probably be held onto the computer's case with a small screw. Undo that first.
Before you work on computers, make sure you wash your hands and touch something metal - this will get rid of static electricity from your hands which could be discharged into the computer's components, damaging them.
Then stick the new sound card in, making sure it's in all the way, and finally, screw the bracked into the computer's case. Then, boot the computer up and install the new card's drivers.
