@pml - I think the medical equipment store will go over any safety and usage questions with you when you get the equipment for your husband but I thought you might find this article from the American Lung Association helpful in the meantime.

-- Oxygen Home Use Guidelines:
https://www.lung.org/lung-health-diseases/lung-procedures-and-tests/oxygen-therapy/using-oxygen-at-home
My wife's twin sisters husband was on oxygen for many years and always took it with on vacation. My biggest fear was stepping on the tubing that came from the oxygen concentrator. Praying that the oxygen will be a blessing for your husband as it was for my brother-in-law.