Yes, start by putting something into the box and plugging it in. Then go to the Aux control panel. The one inside the spa.
There should be a 'mode' label on one of the buttons - all of the buttons do double-duty, and you use the mode button to switch from controlling the jets and lights to controlling the volume and EQ (tone).
The system returns to zero volume whenever the power is interrupted to the amp - like start-up or a water change - so you will not get any sound until you run the volume up again.
There are some trouble-shooting LED indicators on the amp itself, though in some installations they are hard to see: they are on the side of the amp near where the power switch is.
If you get it running and find it needs any parts, let me know: I just discovered a box of goodies in my warehouse: tons of Spaudio items gathering dust.
HTH