I've bought a wifi adapter for raspberry pi, I don't have an OS, I'm running RetroPie so I need a console solution.
Someone suggested accessing:
sudo nano /etc/network/interfaces
and changing it to:
iface lo inet loopback iface eth0 inet dhcp allow-hotplug wlan0 auto wlan0 iface wlan0 inet dhcp wpa-ssid "ssid" wpa-psk "password"
I then reset my device like told and inserted the wifi adapter.
After booting up I don't know what else to do now to connect with wifi...