Mount it onto the Raspberry Pi and you have a stereo audio system. You only have to connect your loudspeakers. It provides up to 60W power. You only need a single 12-24V power supply to power the Raspberry Pi and the Amp+.
It powers the Raspberry Pi, there is no need to add an external 5V power supply to the Raspberry Pi.
The Amp2 is designed to work with all speakers or 4-8 Ohm impedance. It supports sample rates from 44.1-192kHz.
The speaker connections are the same as on the Amp+.
Note that the polarity of one channel is reversed compared to the Amp+. Check the prints on the PCB for the correct polarity!
If the software you’re using doesn’t provide the Amp2 as an output option, you should use the HiFiBerry DAC+ driver as the Amp2 is basically a DAC+ with an integrated power stage.
The Amp2 integrated voltage converter is powerful enough to power even the new Raspberry Pi 4. Just note that it is not designed to power additional power-hungry USB devices or other hardware. There isn’t a problem with low-power devices like mice, keyboards and similar. There might be even enough power for external hard disks, but the system might become unstable if too much additional current is drawn from the USB boards or the 5V rail on the GPIOs.