You cannot file for contempt in Yakima County, if your (previous family law) order was not entered here.
There is no filing fee to start a contempt action. Generally, when a contempt proceeding is/has been started, your paperwork will be filed in the same case the initial matter was filed under.
You will have to go to court at least 2 times. The 1st hearing is called Ex-Parte and you will go by yourself, present your documents to the Judge and explain what your complaint is. At this hearing the Judge will assign you another court date, usually about 2 weeks away. You must then have the other party served with copies of your documents and notice of the next court date. You must "confirm" this hearing, refer to the Guide to Confirm - Confirmation of Hearings (PDF) for more information. Both of you will appear at the 2nd hearing. At that time the Judge will decide if the other party willfully violated the court order.