The main burner unit srews onto the support arms and into the std cannisters. The bottom part is the folded up supprt arms.
The arms slide out and lock into the heat resistant plastic. A quick and easy fit.
In use it is a ferocious wee burner and boiled a pint of water very quickly. Reasuringly noisy.
As with all gasburners it needs a windshieled so I'm designing one just now with a snap on heatshield for a pan too, hopefully working like a heat exchanger.