WARNING: This page is about a different car, the 2001 Subaru Impreza. However, it is still accessible from the selected car via links, so may be relevant.
Install in the reverse order of removal.
Tightening torque:
T:
4.4 N.m (0.45 kgf-m, 3.3 ft-lb)
Fig 1: Tightening Nuts Of Sub Fuel Level Sensor Mounting Plate