Words understanding: released, commence, setting up

hello,
I feel a little bit confuse on some words in following sentence:

After take-off, the cabin crew were released by flight crew to commence duties and to start setting up the cabin service. Passengers were seated with seat belt signs on.

‘released’ here means set them free?
‘commence’ here means get down to do sth or carry out or implement?
‘setting up’ means to prepare the service?
‘with’ here means when?

thank you for your answers.

Hi,

In this sense ‘released’ means were free to start their work. ‘Commence’ means ‘start’ or ‘begin’. ‘Setting up’ means ‘preparation’.

‘With seat belts on’ means they were wearing seat belts.

Alan