(mount sd card)
touch /boot/ssh
cat > /boot/wpa_supplicant.conf<< EOF
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1
country=DE
network={
ssid="YOUR_NETWORK_NAME"
psk="YOUR_NETWORK_PASSWORD"
key_mgmt=WPA-PSK
}
EOF