How to retrieve data using EF Database First

I have a console application. I'm trying to use EF Database First. I used ADO.NET Entity Data Model, then EF Designer from Database. Then I connected to the database, and classes are generated. Now what should I do to retrieve the data of these classes? Here is my empty Program.cs file :

class Program
{
    static void Main(string[] args)
    {

    }
}

Thanks.

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Link to original article：https://stackoverflow.com/questions/39825319/how-to-retrieve-data-using-ef-database-first