I'm trying to buy the Paseo del Arte on the Prado tickets sales website, but I can't figure out exactly how it works. I understand that you can visit them on separate days, but on the website, it asks you which day you want to go and what entry time you want. I assume this is specific to your Prado entry. But does this mean you can go into the Thyssen and Reina Sofia other days at whatever time whenever you want? It's just a bit confusing to choose a day; we hope to go to one of the other two museums on the day before the Prado and want to make sure we can get in.