Abdul,

It is very difficult for you to get into NIT still there are few options available for you and they are

• HNB GARHWAL -MECHANICAL ENGG
• IIEST SHIBPUR METALLURGY ENGG
• School of Engineering Tezpur Food Engineering 
• School of engineering tezpur Mechanical engineering 
• Sant Longwal Institute of Technology.

You may check other options at 

 https://josaa.nic.in/webinfocms/Handler/FileHandler.ashx?i=File&ii=139&iii=Y

You will get admission in this colleges through Josaa Counselling. It will start after declaration of Jee advanced result. May be at end of june. 

You have to apply online and there no charges to apply.  The rest necessary will be shared to you by Josaa at its official website.  Keep checking Josaa website and it's update on Josaa.nic.in ( Josaa 2019).