Different editions have different access methods. For example, the hybrid edition of the "Aula internacional Nueva edición" states that the audio files are available on campus.difusion.com can be downloaded for free from a specific official link: difusion.com/ai2ne_audio . Check your specific book's introduction or back cover for such details.
European and Spanish learning communities on VK often share direct cloud drive links (like Yandex Disk) for textbook audio. You can find these curated threads by searching for "Aula Internacional 2 A2 audio" on the VK platform. ⚠️ Important Warning on "Free Download" Sites aula internacional 2 audio free link download
Many public libraries and university libraries have a (Media Library). They often lend out a CD version of the book. If your computer doesn't have a CD drive, you can borrow the book, take it home, and rip the CD to your computer using Windows Media Player or iTunes. This creates your own personal MP3 backup. Different editions have different access methods