Program.cs
 

using System;

namespace MyApplication
{
  interface IFirstInterface
  {
    void myMethod(); // interface method
  }

  interface ISecondInterface
  {
    void myOtherMethod(); // interface method
  }

  // Implement multiple interfaces
  class DemoClass : IFirstInterface, ISecondInterface
  {
    public void myMethod()
    {
      Console.WriteLine("Some text..");
    }
    public void myOtherMethod()
    {
      Console.WriteLine("Some other text...");
    }
  }

  class Program
  {
    static void Main(string[] args)
    {
      DemoClass myObj = new DemoClass();
      myObj.myMethod();
      myObj.myOtherMethod();
    }
  }
}

Result:
Some text..
Some other text...