To read the magazine on your pc/mac do the following:
At the top of the site, hover your mouse over "Magazine" and click "Read the current Issue"
From there, click the PC/Mac button.
At that point, since you haven't been here before, it should take you to a page where it will ask for your zip code and your email address / power up rewards number.
Enter those values to verify your subscription. After that, you should be reading the digital magazine. Enjoy! :)