To configure band steering on the EAP245 you need to run the EAP Controller. I'm not sure wether band-steering is turned on automatically with default settings in standalone-mode, but I'm sure that you need the EAP Controller to fiddle with its settings. However, band-steering makes sense only if you expect more than, say, 20 to 40 simultaneous users of your AP. For a home network with a few clients only band-steering does not make any sense. You could configure the multi-media devices to always use the 5 GHz band, which makes more sense in order to use the faster bandwidth available in the 5 GHz band.

One SSID for both frequency band is possible (even w/o band steering) and mandatory for band steering.