Filing and Service of paperwork.
This involves what is called a Summons and Petition for Dissolution. These are 2 separate documents that initiate a case. You file them with the court paying a filing fee and then usually have a process server "personally serve" the other spouse with these papers. This begins the 90 day waiting period clock.
Although not mandatory, parties will often want to put in place a temporary order that spells out what happens while waiting for the case to be finalized (after 90 days) and while it is in process. Temporary Orders are obtained via motion by one or both parties, or can be done by agreement. Temporary Orders are just that - "temporary," meaning short-term solutions to hold the case in tact until final resolution. It can include temporary visitation/custody, temporary child support, temporary alimony or other financial issues, resolution of monthly minimum debt payments, financial restraints on both parties (i.e., nobody can cash out a retirement or sell off assets), and other matters. Again, some temporary ruling does not mean that decision will be final.
Wait at least 90 days.
The "cooling off period" is 90 days, which means that after filing and service of the divorce (Step 1 above), everyone has to wait at least 90 days. This does not mean that you can get divorced in 90 days because all final issues have to be resolved before you can enter the paperwork on the 91st day, such as all property and debt divided, all child issues (parenting plan and child support) resolved, and other financial issues have to be resolved, such as spousal maintenance, or attorney's fees. I have often heard people say, "I can get divorced after 90 days, right?" and are dissappointed to learn that the answer is "yes" only IF all issues are agreed and signed off on by both parties.
Entry of Final Papers
This step is the easiest if all final issues are agreed and settled. The parties just "enter" the paperwork in court, which means a judicial officer (Judge or Court Commissioner) approves of all final wording, signs the documents, and then files the original final divorce paperwork. Nobody is divorced until the signature of a Judge is obtained and the paperwork is filed with the clerk. The "if" is the harder part, meaning that the spouses can only enter final papers by this stage 4 "IF" they have agreed to resolution of all issues. Often clients without attorneys think they have resolved everything, but attorneys are aware of all the issues (like a checklist) that need to be addressed and if not addressed, realize could lead to problems if not addressed.
Mediation is a very important tool that allows parties to sit down, usually with their attorneys, with a qualified mediator, who will assist in trying to achieve a settlement. Mediators are usually experienced attorneys in the community and are neutral. This is one form of what is called ADR (Alternative Dispute Resolution) and is often becoming a mandatory step in most counties. It is an alternative to going through the expense, risk, and heart-ache of a full blown trial. However, timing of mediation is important. I have heard many misinformed spouses to a divorce state that they want to mediate before filing. This is possible, but likely not going to be successful because the issues and case must be "ripe" and information must be gathered and exchanged to ensure that parties (and attorneys) are not operating in the dark. Mediation is less formal and more relaxed than a trial.
Trial Before a Judge
Trial before a Judge is the final step if settlement on their own or mediation does not resolve all issues. Trials are expensive and sometimes are described by saying, "trials for a lawyer are like surgeries for a doctor." Trials are the most complicated work a lawyer can do and you should ensure that the lawyer you hire, to take you through steps 1-5 above, is a competent trial lawyer in the unfortunate event that the case goes that far. Hopefully, through negotiation, settlement talks, and eventually mediation, the case can be resolved before trial. But if not, a divorce trial in Washington involves calling witnesses to testify and entry of exhibits for the Judge to rule upon and resolve all final issues. Trials are more formal and less relaxing for clients than mediation.