Without even a lazy, cursory look at the website, I'm going to venture a guess...
You'll probably find your HD held in with one or two screws. You'll remove those, pull the cradle out, and find four to six more screws holding the drive itself in the removable cradle. You'll remove those, and pull the interface adapter off of the drive. Then you'll spin around, hokey-pokey optional, and insert the new drive the same way.
A word of caution: Not all laptop drives will work in all laptops. They are not generically interchangable. Make sure you check with your manufacturer for the specs you need to look for in a replacement.