Given an instance of the struct, you set the values.
student thisStudent;
Console.WriteLine("Please enter StudentId, StudentName, CourseName, Date-Of-Birth");
thisStudent.s_id = int.Parse(Console.ReadLine());
thisStudent.s_name = Console.ReadLine();
thisStudent.c_name = Console.ReadLine();
thisStudent.s_dob = Console.ReadLine();
Note this code is incredibly fragile, since we aren't checking the input from the user at all. And you aren't clear to the user that you expect each data point to be entered on a separate line.