Yea, "besides" does not make sense in this context. However, ademas has many meanings: also, besides, further more, in addition to, moreover, too, again, else, etc. The takeaway being, ademas is adding new information, as Marina described.
¡ Muchísimas gracias! ¡Saludos de Nuevo México! Yo soy un estadounidense y yo quiero aprender Español entonces puedo hablar con mucho gente desde hispanidad! ¡Que Viva! ⚔️🇪🇸🇺🇸🇲🇽⚔️
Thanks for this! I'm trying to improve my listening spanish, as soon as an unfamliar sound patten appears it sort of breaks my understanding and being able to follow along, and a lot of these have been connector words and idiomic use of words