Hi Ravi,
I would like help you, but give me an idea please what is your level of technical knowledge and what you need?! Are you a technical individual or just a hobbyist looking to learn to read technical illustration! the reason for asking is that 2D drafting is not a universal description; for example, 2D drafting for Mechanical engineeering is different from 2D drafting for Architects or even 2D drafting for Civil Engineering.
I can point you to some of the document to help based on your needs,
Regards,
Mo