Designing a social networking site

I do not have a software development background yet I have developed an application for android based phones and tablets that can aid in Lecture Noting. Using this application, users can take lectures on their tablets and store them in it. My next task, after developing the application, is to develop a simple social networking site in which different users can upload their lectures and users that are friend of each other can share thier lectures and comments on it. The lectures are to be uploaded directly from my applica开发者_JS百科tion in android device on the social networking site categorized by that particular user.

Since I have never worked on website development, I would like to know the beginning point i.e what topics should I start studying....which database to use for this task...how to integrate this database with the website...etc

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The list of things you'll need to know is a lot longer than merely picking a database:

1. HTTP
2. HTML, CSS, JavaScript for clients
3. SQL and relational databases

This isn't a trivial task even if you already have a s'ware development background.