By a table with several boxes and two coffee cups on it, a woman in a green sweater is opening a small box and another person (whose head cannot be seen) is operating a small handheld electronic device.
A woman in green opening a box while a half concealed man manipulates a handheld device.
Woman in a green sweater implies woman in green, and operating is manipulates.
A woman in a green sweater would be a woman in green. Another person would be a man. A box can be small. Manipulating and operating have the same meaning. A handheld device is a small electronic device.
If there is a person (whose head cannot be seen) then that person is half concealed.