Hi Manu, 

We recently had an AMA (Ask Me Anything) with Bishnu Adhikari. You can follow his workout and diet plan here:

http://fitfreak.healthkart.com/content/bishnus-workout-plan

http://fitfreak.healthkart.com/content/bishnus-diet-plan

Thanks!

Dude you must give a try to Dymatize Super Mass gainer or BSN True Mass,they r bit expensive than Muscleblaze but u will get results with proper diet and workout,see the improvement after 1 month only!

you should go for high cal mass gainers which have protein: cabs:: 5:1, because as Vishant says you need to gain 20 kg muscle mass. 

Along with this you should have 6 meals in a day and intake more water around 4-5 ltr