Hi,
The best and only way is to use network. Trying to put roms on the SD itself requires Linux + a little knowledge of linux permissions
So, as of recalbox 4.0 that doesn't reconfigure network on the fly, you must :
- either boot with a ethernet usb, transfert your roms
- either set wifi with a usb keyboard, poweroff, plug yuor wifi dongle, reboot, and transfert through network
Having a USB hub may come handy