Vim3 android kernel update

How did you build your onw android kernel?
I spent days on this topic but just got stuck. Looking forward to having your suggestions :]

Google’s guide for building VIM3 Kernel on Using Reference Boards does NOT work on my Ubuntus 18.04 VM. I met too many build error while running it.

And @numbqq replied me on this topinc - please do not use Fenix to build anything of android . He suggested that fenix should NOT be used to update Android. Just for your reference :]

Thanks.