The power steering fluid reservoir is located on the driver's side of the motor to the right of the valve covers and closer to the front. There is a cap w/a short dipstick on the top of the reservoir. You can tell its power steering by looking around or under the fluid reservoir-you will see the power steering pump and the belts.
The 1995 3800-11 is a transverse engine, with a single serpentine belt. The Park Avenue I have has the PSP at the rear of the passenger side and near the firewall. Standing at the passenger side and looking in at the engine, the PSP is to the left and the lower pulley to the rear, under the alternator. (which I found it easier to remove to reach the pump) The reservoir is on the rear of the pump with the cap hard to see except when looking straight down at the top of the pump. The pump has bolts reached through holes in the pulley, and the hoses may be easier accessed after lifting the pump. All I did was turn the steering wheel from lock to lock a few times to purge air from the system after filling it. ymmv
Maybe I was lucky because I can envision this job becoming a PITA.