To check the power steering fluid level:

Remove the right front tire.
Remove the fender liner.
The 10" tall cylindrical thing in front of the wheel well with FoMoCo on the side is the power steering pump and reservoir. The fluid should be between the min and max lines.
To add fluid you can use a transmission funnel through one of the holes in the radiator support. To get the cap off you need to remove the right headlight. It is easy. Pull out the retaining clip and move the headlight assembly to the right side of the car (as seen from the driver's seat). Unplug the headlight rather than leave it hanging by the wiring harness.
Use Pentosin CHF 11S, the green stuff. It meets Ford spec WSS-M2C204-A.

To change the fluid:

Do all the above except adding fluid.
Pick up two liters of fluid. It is $20+ per can.
Cut a piece of cardboard 6" wide and 2' long. Bend it lengthwise to make a trough. Use piece of wire or tape to keep it in a V shape.
Pull the bumper valance down and wedge the trough between the pump and the lower control arm to direct the fluid into your drain pan.
Remove the return hose and the pressure line to drain the fluid. I got 7/8 of a pint.
Reattach the lines, add the same amount of fresh fluid back to the reservoir. Remove the trough.
Start the car and let it idle.
Turn the steering wheel lock to lock a dozen times.
Shut off the engine.
Remove the lines and drain the fluid.
With two liters of fluid you will have enough to repeat the process five times.
The fluid will not be all new but it will be much better than what was in there.