The newly appointed supervisors shall, after their bonds are duly approved, meet the first Tuesday in December following the election adopting township organization. They shall at once organize by electing one of the seven supervisors as chairman, who shall appoint all the necessary committees. From and after such meeting and organization the powers of the county commissioners shall cease and the board so organized shall have all the powers, and perform all and singular the duties performed by county boards as contemplated by law.
Neb. Rev. Stat. §§ 23-208