Plug the USB-A side into your computer.

Plug the other side of the USB into your 3D printer.

If you purchased your machine new, it came with the proper cable.

We suggest you use X Loader for PC and Hex Uploader for Mac computers (requires Arduino IDE to be in your Applications folder)

Prusa Slicer works very well for flashing .hex files with Atmega2560 chips (type used in CR-10S Pro)

FIRMWARE

Go to http://bit.ly/2DIIXNi to find files and firmware flashing info.