We routinely assist unmarried parents with establishing residential schedules, decision-making provisions and other helpful co-parenting tools through parenting plan and child support orders. Washington Law Help’s guide to Parenting Plans can be a helpful resource when researching basics: https://www.washingtonlawhelp.org/resource/parenting-plans-court-orders-about-child-cust.
See also the Divorce tab for some basic information on Parenting Plans and Child Support.