Hi learning,
here is the circuit according to ST suggestions. I placed all parts exactly as shown in the application and enlarged the ground area for sufficient cooling (if you don't use a heat sink).
If you make the PCB double sided you don't need any vias, but have the entire top layer as cooling area.
The application has a minor flaw. C6 is a dual part, once as non polarized capacitor of 100nF, connected to the left channel output and once as electrolytic cap, connected to signal ground and the the positive terminal connected to pin2 of the amplifier IC (which is not connected internally). I omitted that one.
Boncuk