It's not easy to describe by words alone. Attach a picture, which is easy to understand and more intuitive. Although it is not the brand of Ainuo, otg has similar functions. The picture inside shows the otg cable (short), usb cable (long) and MP4 connected to the USB flash drive. After connecting, you can open MP4 and select usb devices from music, video or other options to read the contents of the USB flash drive. The same is true for connecting other devices (such as MP4). By the way, there may be some problems in identifying when the power is low. Try to ensure that the power is sufficient.