Entity Relational Diagram on C# Database Connection

Hello I am currently working on a project for my database class. I have created a database in Visual Studio 2013 and I have connected it to a C# Windows Form Application. I am trying to create an Entity Relational Diagram where I can see the table relationships on the Visual Studio database I have created but, I do not know how. can anybody help me? I posted this on C# because I am using C# to insert data into my database but, if there is another forum for this question let me know and I will re-post there. Thank you.