Good evening, forum's members!! Although I have Windows 10 on my laptop, I plan to return to Windows 7 due to the network adapter driver's incompatibility, failure that prevents the laptop from automatically connecting to my internet, forcing me to run the network diagnostics every time I turn the laptop on.

I've clarified some doubts with a person who trades Windows 7 licenses on a varied shopping site, such as E-Bay.
He told me that, after payment, he would send the Windows 7 license activation link via e-mail.
The installation of Windows 7 is conditioned on the formatting of the laptop.
I would like to elucidate three doubts:
1) Could I perform this formatting myself?
2) Do I need advanced support to do it?
3) After performed formatting, how could I access my e-mail in order to install Windows 7?
PS: In Windows 10, from the Start menu, I accessed:
Settings / Update and Security / Recovery, on the left side of the screen.
On the right side, there is the option "More recovery options. Learn how to start from zero with a clean installation of Windows".
When you select the last sentence, another window appears with the following explanation:
"Restart by reinstalling and updating Windows. This will keep your personal files and some Windows settings and remove most of your applications, including Microsoft Office, third-party anti-virus software and desktop applications that came preinstalled on your device".
Could I perform the formatting from the procedure above?
Best regards
Mascibran