Flashing to BBB eMMC

Hello,
I want to flash the diskimage to the eMMC and I dont know how to do the final steps described here: Flashing eMMC. Can someone help me I dont know how to use the nano interface.

"ctrl" + "x" = exit and save

Ready to go flasher images are now available on beagleboard.org now:

https://beagleboard.org/latest-images

Regards,