Tablet [Q] Porting from JellyBean 4.2.2 to Kitkat 4.4.4 for Exynos 5250 based YSE5250

Hi,
I have been working on JB sorce code for Exynos 5250 based YSE5250 board. It works fine with JB 4.2.2 and is tested on board.

I need to port this board from JellyBean 4.2.2 to Kitkat 4.4.4.

I went through few referances like youtube.com/watch?v=mvxYt3AkbrEand "Embedded Android" by Karim Yagbmour.
I also went through google's official porting guide source.android.com/devices/index.html

I downloaded aosp project and exynos kernel from google git and tried to do changes according to above references. But I am facing issues while building source.

I am still confused about how I proceed with this task.

Is there any good tutorial or procedure to port boards to android or porting existing Android JB to Android KK?

Any directions/help will be appreciated.
Thanks,
Sunil.