Many carders choose Windows 10 as their operating system. But everyone knows that it works as a keylogger and transmits all actions to Microsoft servers. I think Windows 8 is not completely safe either. The operating system should be similar to the cardholder's regular computer, including changing the language, keyboard layout, time zone, and time.
Currently, most cardholders are using Windows 10 and Windows 11. Therefore, you need to choose from these options.
If you chose to work via Firefox, you can read this manual:
Nevertheless, I advise you to try and learn on any free anti-detect browser.
In any of these options, you always need to add a crystal clear socks5 proxy to them. Before registering an account or making a payment, you need to check the quality of the proxy on specialized sites to avoid leaks.