Listening to gentle music during the meditation is fine. If absolutely necessary, getting up slowly to use the toilet or get a drink of water is fine but go back to the meditation straightaway. No reading or screens.
Don't go out and about while your booked meditation is taking place. No alcohol etc on session day and preferably not the day before or after either.
If you do happen to go out and about whilst booked into a meditation for whatever reason, the Divine Cosmic Energy will place you into a gorgeous cocoon of love, peace and protection but you will not receive any other energetics. This is for your wellbeing while you are on the move and the overall group harmony.
Rest post meditation to let the powerful energetics assimilate and feel free to drift off to sleep. If you must listen, read or watch anything, avoid all negativity in the content. Avoid engaging in conversation post session as well, especially banal or negative conversation.