Welcome to Android Central! I can't find the actual manual online for those headphones, but the FAQ suggests that you can only transfer files from a Windows or Mac computer using the included cable: https://naenka.com/pages/product-faqs#:~:text=A: Use the magnetic charging,computer to the headphone's memory.. You could try connecting it to your phone (which presumably would need a USB-A to USB-C adapter), but I don't know if it'll be compatible. If nothing shows up in a file manager, then it won't work.