Extracting Sitecore Analytic Data

I’m new to Sitecore concepts, and I’m searching almost five days for an answer. I couldn’t find what I’m looking for.

I’m trying to access Sitecore analytic data from a web service. I found a web service of Sitecore with using this document. I want to extract data that are about this. I believe this is a public demo site

I want to access Web Api, then extract data and use it at my own project. Any idea?