You have three options when deciding who will manage and/or build your project:
Hire a licensed contractor. The contractor will manage the construction of the building(s) covered by your permit on your behalf. The Washington State Attorney General's Contractors website might provide you with helpful insight if you choose this option. If hiring a contractor, they must have a current, valid license.
Act as Owner Contractor. The owner of the property/parcel functions as the contractor. An Owner Contractor may do some of the physical building, but is more likely to hire subcontractors and manage the construction project as a Contractor would. An Owner Contractor must hire subcontractors that have current, valid licenses.
Act as Owner Builder. The owner of the property/parcel physically builds the structure covered by the permit. See San Juan County Code 15.04.540, which regulates owner builder projects.