The Mac App Store is really a dream to navigate, especially if you are used to the iTunes store. It’s very similar to that. Although you can’t browse the Mac App Store from your iPad magical device, or your iPhone, you can use any iTunes gift cards you may be around within the Mac App Store – that’s a nice touch, especially if you have a few around from Christmas.
From the main menu of the Mac App Store, head over to Redeem and click once.
From there, just enter the Redeem Code and click on Redeem – your brand new Mac App will then start downloading – enjoy!