Without a computer, how can I transfer the square dance video to the memory card with my mobile phone?

At present, you have to have a mobile phone with an external memory card, which is rarely used by people at present.

When you insert the memory card into your phone, open the settings, select Save, and change the storage location to the memory card.

Then download the video of square dance, and then have a card reader. Take out the downloaded mobile phone memory card, put it in the card reader and check it on the stereo.

The above things are indispensable.