Based on that tutorial you don't need to change page link. On same page you can do that. Like section/button for Mac/windows.
Here how you can do:
Step1: Add the code on your functions.php then you will see on your website under body tag have a specific class if you are form Mac then "osx" or if you are from windows then "windows"
Step2: add class on you Mac section called "osxsection" & for windows section "windowssection"
Step3: Now do the css like this:
// to view the section on Mac
.osx .osxsection {
display: block !important;
}
.osxsection {
display: none;
}
// to view the section on Windows
.windows .windowssection {
display: block !important;
}
.windowssection {
display: none;
}
you can present that CSS code some different way also.
Try that hope it will help you :)