Getting Started- Unity & Hololens 1

Setting up developing environment as a complete novice isnt easy sometimes. I am writing this to my future self should i encounter similar trivial problems. Documentations on official page is good but there are still things to watch out for. Official getting started can be found here :

https://docs.microsoft.com/en-us/windows/mixed-reality/holograms-100
https://docs.microsoft.com/en-us/windows/mixed-reality/install-the-tools

Look for answers below IF:

Unity Build settings do not detect any Visual studio, Restart PC ( Note that Unity MUST install AFTER VS )

During build, Error : cannot find SDK of previous version, Open Visual Studio Installer -> Modify, add the version needed

During Build Error: could not find SDK verXXXXX , simply delete those files from the project tree in Visual Studios

Visual Studio does not show deploy target, go to installer -> modify -> under UWP, check, USB device connectivity