Starting a Coroutine

 Inside a MonoBehaviour script call StartCoroutine.

Create the Courotine method:

private IEnumerator DoSomethingCourotine()
{

    // Do Something
}

Call that courotine method, by name: 

StartCoroutine("DoSomethingCourotine");

With Parameters, create the Courotine method:

IEnumerator DoSomethingCourotine(string doodle) 

{

    // Do Something

}

Call that courotine method,: 

StartCoroutine(DoSomethingCourotine ("parameter") );