Good Day! I am a beginner and exploring odk forms, and I am having a hard time how to add new record if your answer was not in the choices. I am practicing making simple forms. Thank You! 
Hi
Insert another answer (miscellaneous e.g.) in the same question. Then add a type text line in Excel and set up the condition that only with the answer other this text input appears.
You may find it helpful to look at this example from the documentation.