How can I extract data using API with visual C dot net


I’m just a beginner and I want help in extracting data from twitter using API
I don’t know from where I should start, and I have read many topics that confused me!
I read about many things but I couldn’t understand them.
What I need to extract is the people opinions about anything then classified them based on their opinions
So from where should I start?
I will use visual C dot net

I appreciate any infirmation