HELP! Chuwi Hi10 Plus!

I have a tablet on android 5.1 and windows 10. And I lost Windows 10 on the tablet.
How to reinstall it first, but save the android?
Please tell me where to download, and how to do this.
Thank you!!!

Model CWI527
Chuwi Hi10 Plus LQ64G42170201656

Thank you!
don’t know how to do it?
is there any instruction?