[Wishful]

If the NB is assembled properly, center the left dome over the left breast and hold snuggly. Then center the right one over the right breast and hold snuggly. You can hold both with one arm with a bit of trial and error. I have been doing it for a couple of weeks and its still a bit tricky to hold but its getting easier. then with the free hand start pumping watching the breasts. They should start suctioning into the domes. Continue to pump until you feel a bit of pull on the breasts but NOT pain. Stop then and wait. If the pressure seems to let off a bit due to the pump leaking, pump a little more until the pull returns. At the end of the desired period, press the release button to release the suction and remove the domes.
Thats about the best we can do for a step by step. There is a paper included with the NB when you buy it that gives a lot of good advice. Read it carefully. If you didn't keep it, let us know and someone here can arrange to send you a copy.
Anyone have anything to add to my attempt? Maybe I can learn something here, too.