If you’re using LXDE, you can probably skip all this and use the wpa gui application.
All you have to do is plug in your WiFi adapter and make some changes to /etc/network/interfaces
sudo vi /etc/network/interfaces
My interfaces file looks like this. I commented out three lines and added the third lines at the bottom.
auto lo iface lo inet loopback iface eth0 inet dhcp allow-hotplug wlan0 #iface wlan0 inet manual #wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf #iface default inet dhcp iface wlan0 inet dhcp wpa-ssid
Save the file and reboot.
sudo shutdown -r now
Hopefully you now have a working wireless connection.