There is a good amount going on with the Conn Electric Band's configuration, but nothing that I found very complicated as a lot of it is buttons for choosing your sound. On the far left there is a control panel for choosing your rhythm drum loops/patterns, along with further configuring your left hand/right hand split, reverb level, and overall volume control. It then has a series of buttons for choosing your preset sound, all of which are emulations of acoustic instruments and includes settings for brass, harpsichord, bassoon, clarinet, piano, and a number of others. On the far right is a series of sliders for further affecting your tone, including parameters for tone, wa-wa (filter), speed and depth for the modulator effect, and sustain. A manual should not be needed, nor have I seen one myself.
The Conn Electric Band is a really cool, vintage all in one workstation. Of course keyboards like this have come a very long way, but there's a lot to be said about these earlier models as they have cheesy sort of sounds that can provide something that isn't really taken into account in more modern keyboard workstations. It's got vibe and character and is certainly unique. The sounds aren't going to be very realistic, but they sound cool by my ear and I can definitely see how these sounds would be useful if you were going for this sort of vibe. I don't know too much backing information the Conn Electric Band, but it's definitely a cool keyboard worth checking out if you ever get the opportunity.