To do this, buy a special USB stick with the correct adapter for your phone. For a Samsung S8, it's a USBC on one end, and a normal USB2/3 on the other, with a memory card inbetween. Here is short film on how to do it.
Here is a link to the USB dongle product used in the video.
https://www.amazon.co.uk/gp/product/B07YYJ63VF/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1