You might want to explain what an OS is, since many people have no idea. I explain it like this:

“Hardware is the machine you use, like a phone or computer. Apps and games are software that run on that hardware and let you do stuff. But in order for your software to run smoothly on your hardware, another collection of software is needed to allow them to interact. Collectively this bundle of code can be called an OS or Operating System. The most common one on computers is Windows, followed by macOS, ChromeOS and Linux. Your phone runs iOS or Android (usually).

Some torrents are available for Mac, most are meant for Windows since it’s more popular and has fewer restrictions on what can be installed by users. In any case, you should always check that the app you’re downloading is going to work with your operating system.”