I just bought this house with a Stewart Warner saf-aire wall heater and I don't know how to operate it. I need to print a manual of some sort.

I just ran into this and this is how I did it:

Locate the pilot light relight hole. On mine it is under an orange cap that screws off, on the right side and above the OFF/PILOT switch. Unscrew the cap and set it aside.

Turn on the main gas valve. Should see a gas pipe in there with a valve/handle that turns to open the gas. It is in different places in each installation based on the house.

Push down and turn pilot/on switch from OFF to PILOT.

Take a long lighter (like to start a barbecue... or you could use a long match) and put the end in the hole. Match will go right in, lighter will rest against the hole as it won't fit in there.

Now, while holding down the pilot switch, click the lighter to light the pilot. Hold the switch down for 30 seconds. When you take the lighter away, you should see the pilot through the pilot hole, but it won't show in the black square window. (it only shows there when the furnace actually ignites). If it didn't light first time, try again.

Once lit, turn pilot switch from PILOT to ON. The switch turns counter-clockwise and ON it toward the back.

Note that if your thermostat has a setting for HEAT and OFF, make sure you move it to HEAT.

To turn off for summer: just turn the switch from ON to OFF by turning clockwise and turn the gas valve off. When open, the gas valve is straight with the gas line. When closed, it is perpendicular to the pipe.