How to parse json data in c#

Question

I am building educational app for windows phone app for my project But i dont know how to fetch data in it, I am using xampp for fetching datas i have created database and api is also ready, My project contains 3 pages 1.Mainpage,2.Section,3.Itempage and our Mainpage will remain constant but Section page should change So i am confuse where to call data and how to do that . and our some data are defaultly are in it using JSON already

 

Link for source code

  https://drive.google.com/open?id=0B7Uq9O_zExMKYUVWLU1fTXZpX1E