You would need to book in advance. There are only 15 people allowed in per day (exceptions: see link below). You will also need a car to get to the entrance (following the guide) which is some distance away from the city where you book/start. The cave is slippery and some agility clearly is of advantage. Tour is in Spanish, but leaflets in English are provided. Fee was 10 Euro in 2019. Here is a link providing the details: https://www.juntadeandalucia.es/cultura/agendaculturaldeandalucia/evento/visitas-la-cueva-de-ardales
Something is not right. This message is just to keep things from messing up down the road