WARNING: This page is about a different car, the 2002 Nissan Altima. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Identifying Oil Pump & Components
Courtesy of NISSAN MOTOR CO., U.S.A.
Disassemble as shown.
Assembly is in the reverse order of Disassembly. When assembling the oil pump, apply engine oil to the rotors.