Hello Friends,
Firstly sorry for taking such long time for updating this thread. Here are step by step Update:
DIY Installation Step 1 (HEAD UNIT INSTALLATION):
Installed the Head Unit at stock location. This was very difficult step for me as I had never done anything like this before (M800 installation is very easy I must say as I did that on Dad's car long back). I had to look around every possible option i could so that installation looks professional

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Removing the Dash Garnish of the HU stock location was a pain as i dint know which all screws had to be removed

. I have a limited version Alto so I actually removed all the screws of the front garnish and later realized that most of it was not required so had to rescrew the same (when i realized that lower portion is independently removable). Wasted a lot of precious time for this step. After all this i opened up the cradle where head unit was to be fitted (the iron thingy).