Go to the tutorial and follow instructions.

If you are seeing this error, it means that the device needs to be reset:

unable to locate any volume: [RPI-RP2]

When the device is connected to your computer, press both the BOOTSEL button on the board, and the reset button (both are located in the back of the badge) for 5 seconds, then release the reset button first while still holding the boot for another 5 seconds to reset the device and allow tinygo to flash the device.

The device might disconnect after being flashed, you need to reset it each time before flashing it (e.g., for each step of the activity).

If the problem persists, try holding BOOTSEL while connecting the USB cable to your computer. This puts the device in USB mass storage device mode.

$ fdisk -l
...
Device     Boot Start    End Sectors  Size Id Type
/dev/sdb1           1 262143  262143  128M  e W95 FAT16 (LBA)

Make note of the device path, which may be different on your system (e.g. /dev/sda1).

On Linux, ensure that the device is mounted with a volume name of RPI-RP2:

$ mkdir /media/RPI-RP2
$ mount /dev/sdb1 /media/RPI-RP2