I have an old well/cistern on my patio . House was built 1904 and I think this was primary water supply at that time. There's a well structure with a chain type pulley system to lift water out now. The well structure near the top is 39" tall, then the cistern widens out below that. The top box is concrete and has a interior size of 22" X 20 3/4 ".
I want to use the water, which is 14 1/2' below the top of the box OR it's 11'3" from the bottom of the box. Water depth is 4' and I don't know exactly how wide the cistern is at the bottom, but even in the drought, the water level remains stable.
There is the remains of three small ledges at the bottom of the box, where I believe I can install a triangular shelf that could hold a pressure tank and a pump, or I could suspend one of them from an iron ring that is embedded in the concrete box.
This is for garden irrigation, probably just using a water hose. We have extensive flower gardens all around the house.
What would you recommend in terms of pump, pressure tank or no tank?

We did a fake well ( with bucket and a "bird bath to pretend to be the well" and under it we housed the well pump.

A shallow well pump and a small bladder tank would take care of your garden needs. This could be installed on the shelf or on the surface. Good luck, Tom

We did a fake well ( with bucket and a "bird bath to pretend to be the well" and under it we housed the well pump.

About how much space does this take?

A shallow well pump and a small bladder tank would take care of your garden needs. This could be installed on the shelf or on the surface. Good luck, Tom

About what size of space would be needed for this set-up?

If this is for a garden hose only I would look for a small irrigation pump. Shouldn't need a tank.

I had a pump with a small horizonal tank, it may have been 15 or 20 gallon tank ( if my old memory is right) We build a some what dropped floor a few feet down into the hole but we bought all the pumps and set them up and then build a frame that was set over it.

Harold advised.
Shouldn't need a tank. I was going to say the same thing but it would depend on how much watering you do. Without a tank the pump would run constantly during the draw. With a small bladder tank the pump would get a chance to rest and cool down. Your choice. Good luck, Tom