To buy a combo ticket you have to enter on B-ticket, after choosing the Museum, date and time of your visit you should open the tab “Reduced and combo”:
and choose the right ticket:
We advise you to check the official sites of the Museums included in the combo ticket for informations on the first Museum to visit.
If you are still having trouble in purchasing the ticket you can request support from our operators. Scroll down to this article or in the menu at the top right and click on "Submit a request", filling out the relevant contact form.