The first is to connect the micro: bit card to the computer using a micro USB cable. This done, the card will appear on your computer as a disk called “MICROBIT” which is not a normal USB disk.
The second would be to write the program with Makecode, that is, write the micro: bit code: drag and drop a few blocks.
The third and last step is to send the program to the micro: bit card by clicking on the “Download” button in the Makecode editor, which allows you to download a “hex” file which is a compact format. of your program that your micro: bit can read. Once the “hex” file has been downloaded, it is copied to the micro: bit card like copying a file to a USB stick. In Windows, you can click with the right mouse button and choose “Send to MICROBIT”.