How to compile ayufan repo step by step?

[hisstone]

I am recently buy a rock64 board, when search using google, I found  ayufan repo, so I download the SD card image from release link below: 
https://github.com/ayufan-rock64/linux-b.../tag/0.7.9 , such as stretch-minimal-rock64-0.7.9-1067-arm64.img.xz

[url=https://github.com/ayufan-rock64/linux-build/releases/download/0.7.9/stretch-minimal-rock64-0.7.9-1067-arm64.img.xz][/url]the rock64 can start normal and into the linux system.

But when I changed some config in kernel, what is the step to create a SD image base on some components like: u-boot.img, boot.img, and buildroot rootfs.ex4.

Thanks a lot.