get files onto the bifferboard
The most straightforward (but most awkward) way to get files on and off your bifferboard is to unplug it from the power, put your bifferboard's USB drive into your desktop PC, and copy any files you need onto it, before plugging it back into your bifferboard and powering it up again
If you have networking setup, you can use scp to copy files back and forth, e.g. 'scp mylocalfile email@example.com:myremotepath' (after you've configured a root password)
If you have internet access working on your bifferboard (i.e. you've correctly setup your gateway and dns settings), then you can use wget (included in the base install as part of busybox) to download files from the internet, e.g. 'wget http://downloads.openwrt.org/kamikaze/8.09/rdc/packages/nano_2.0.7-1_i386.ipk'