If you use some kind of a software, please make sure there is an appropriate Windows/MacOS version. Then you simply enter your proxies into the software proxy settings.

If you are going to use your proxies manually, the OS version is irrelevant because you will need to add them to your browser. You can add them to any browser like Google Chrome, Firefox, Safari or Internet Explorer. 

This is how you can set up our Proxies on Chrome browser both on Windows and MacOS.

https://help.privateproxy.me/en/articles/2437199-how-can-i-set-up-your-proxy-service-on-chrome

Another way is to use a Chrome extension like FoxyProxy:

https://chrome.google.com/webstore/detail/foxyproxy-standard/gcknhkkoolaabfmlnjonogaaifnjlfnp?hl=en

This extension allows you to switch between proxies quickly.