I don't have any pics, but my steamer is just a piece of 6" PVC pipe, set across a sawbuck, with one end capped, and the other end removeable.
I cross drilled it about every 8" and inserted dowels across it to make a 'shelf' to hold my stock.
My steam source is a NEW (never used for fuel) 3 gallon metal gas can with a piece of automobile radiator hose fitted to the spout, and a propane turkey fryer burner. Two gallons of water begins to boil in under five minutes, and the steam volume is huge. Thirty minutes in the steamer does half inch stock very well, but you gotta work quickly.
Working time out of the steamer is way less than a minute. You might want to make up half a dozen (or more) forms so you can steam multiples. The bent pieces should stay on the forms at least overnight - I usually wait a couple days.
The bends for your chairs look to be compound curve. You'll probably need to make two-piece molds, and clamp them together to make the bends.
Oh, BTW, expect about a 30% loss due to splintering/breaking, so make some extras. DAMHIKT...