TDA7297 amplifier board gives no sound
The TDA7297 is specified for a single supply, up to 18V. So, it seems your mistake was connecting GND to -12V. It should be connected to ground - that is, the return of your +12V supply.

Because this chip drives the output in a bridge configuration, the differential output signal can go positive and negative with only a positive supply.

It's likely that you damaged the chip by supplying it with 24V when the specified absmax is 20V. You'll want to swap it out before trying again.