Activating RPi 3B+ wifi for interface access

[Skip Pack]

When i attempt to access my Moode system via wifi, (I usually use wired ethernet), I cannot see an SSID for it via the Android interface. Using ifconfig via ssh I see wlan0, but I haven't found a way to establish the SSID on the 3B+. I'll be taking my system to Burning Amp once again, so all music will be local and the control only will access via wifi. I imagine this is very simple but my searches on the Pi side and the Moode fourum haven't gotten me there.

Thanks,   Skip