An unlawful detainer action in Washington requires more than just filling out a simple form. You have to prepare a summons and complaint. The summons and complaint must be filed to open the case. After the case is opened, a motion for an order show cause can be presented to a judge ex parte. The judge will issue an order requiring the tenants to appear in court at the date and time scheduled for a hearing. These documents must be served on the tenant in the proper manner. You must appear in court at the time set for the hearing on the order show cause to give testimony concerning the grounds for the eviction. When the judge rules in your favor, you need to give the judge a written form of judgment directing the clerk to issue a writ of restitution. You then need to take writ of restitution forms to the court clerk. The court clerk will issue the writ by completing your forms. You then take the writ issued by the court clerk to the county sheriff, and the county sheriff will serve the writ schedule the actual move out.
An attorney is not required for landlords to evict tenants, but If you have never been involved in an unlawful detainer action, you should probably hire an attorney to help you with your first.