Solved Dual boot Chuwi h10 2016/17 clean install

Hi, I have this tab, chuwi h10, I use it with Bluetooth keyboard and mouse and it works well for my girlfriends NHS training (that’s all it’s job is right now) I dont use the android operating system that was pre installed anymore.
I re installed windows 10 thinking that that would wipe everything and end up with the one system but now realise it is not that easy.
the tab should have the basic system requirements for windows 11 apart from the SSD is only 65gb (64 available) and the quad (1.44 ghz) processors come up as a problem although PC health check later says that they are good.
my main questions are:
how do I do a clean install of windows 10 which will remove all signs of the ”previous” android 5.1. Baring in mind that I don’t own any installation discs or however windows 10 may be supplied these days, there were no prompts for key when I reinstalled from windows web (pretty sure there is a key supplied with tab though)
and,
as tab can handle 128gb SD card should/can I run operating system, which I would like to ultimately be windows 11 from the SD card or is the 64gb SSD available enough to ultimately install windows 11 but put everything else on SD card?

I look forward to any help anyone can offer me

Ok, so all I can see from the windows side is: intel(R) Atom(TM) x5 Z8350 CPU @ 1.44GHz
the system type is 64 bit

Ah ok, I think I understand what you are saying, the parts of this tab that is running android is completely different from what is running windows and they are completely incompatible?