[Q] How do I make a custom kernel?

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http://forum.xda-developers.com – I'm aware that there are custom kernels for 5.0 by rumirand and entropy, but rumirand's kernel is not really 100% compatible with YP-GB70 (KOR) and this is the device that i currently have. Unfortunately, even in Korea GP forum, there is absolutely no custom kernel for 5.0 (Tegrak Kernel exists for 4.0) So i wanted to develop it on my own so i've been searching for instructions. I've instaled ubuntu, installed bunch of stuffs. but i have no idea how to start. all those guides were incoherent. can somebody tell me some basic infos and things that i should know for developing YP-GB70 k (HowTos)