Disclaimer: All these FAQs and Solutions are taken from my knowledge and experience if anything wrong please point out so I can correct it.And feel free to add more FAQs and Errors from your side
FAQ #1 : Easiest way to setup build environment ?
Answer: Their is a script will will make all the work easy by Akhil Narang XDA senior Member and great dev
Steps to be followed:
git clone https://github.com/akhilnarang/scripts
bash setup/<name of script>