They all include entry to the museum with a booked time slot plus an extra service: audio guide, guided tour or a second combined visit. Each listing states exactly what is and isn't included.

It isn't required by law, but in practice yes: without a booking you join the ticket-office queue, which exceeds an hour in high season. Visitors who book use a dedicated entrance at the time shown.

You'll get the confirmation by email right after payment, with your voucher or ticket. You can show it on your phone; there's no need to print it.