You need to know how to use the Sharepoint client object model. Firstly, you have to get the SP Content -> SP List -> SP ListItems. Here is the complete basic operations using Javascript library code in SP. I think that will really helpful for you: 
[http://msdn.microsoft.com/en-us/library/office/jj163201.aspx][1]


  [1]: http://msdn.microsoft.com/en-us/library/office/jj163201.aspx