How to use sdf database in project.

 Using Microsoft SQL Server Compact 4.0

SQL compact edition is ideal for secluded project where you are not worried about security of database, and is small application. I suppose its good to use as prototype version to display clients data based on database, but not too vital, where you can afford to use backup from whole system and is not crucial  for running 24/7.

You need to install 

Microsoft SQL Server Compact 4.0

http://www.microsoft.com/en-us/download/details.aspx?id=17876

This will give you all basic references and dll files you need to successfully use EF4.3 as I have done.