Will, the bare minimum is: you will need to make an adapter for the engine so that it can be fed air from an air compressor. On the side of the cylinder valve chest there is a valve with a thread on it - this is the thread you need to match, don't expect one to be available off the shelf and what ever you do don't force something on that is the wrong thread
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As for the engine the seal on the piston/glands is probably graphited yarn which may have dried out over the years. What you want to avoid is trying to undo threads in case they have ceased and break, then you have more challenges. Find yourself some sewing machine oil and use that provide a little lubrication to the moving joints. See if you can get a little oil in either end of the cylinder via the valve on the steam chest.
Then try a little air, it probably will turn over on its own. Be careful you don't over do things as there will be little oil in there and maybe an accumulation of dust from over the years.
The next stage: Do you have a "feel" for tightening and loosening screws etc? i.e. do you know when you are putting on too much pressure on a screw relative to its diameter?
Jo