If you open the PC up you'll see your Hard Drive now, on the cable that comes out of it there's an extra port with pins corresponding to those on the back of your new Hard Drive. Put the new one in the tray that the old is it, preferably below, but otherwise in a position where the extra port on the Ribbon it reachable. Plug that in, get another Power Port and plug that in - again from along the line from the old Hard Drive's Power Cable.
There is a little jumper in the back of the new Hard Drive; probably best to take it out but keep it safe in case you need it again.
Then just boot up, and it should be there as another Drive.
A Knight is sworn to Honour. His heart knows only Virtue. His blade defends the helpless. His might upholds the Weak. His word speaks only truth. His wrath undoes the Wicked.