This TDA4935 audio amplifier electronic circuit is capable of delivering a 2x15 w output power in stereo configuration or 30 watts audio output power in mono configuration .<
The TDA4935 audio amplifier integrated circuit can be used with a 4 or 8 ohms load impedance .

If you want to use TDA4935 audio amplifier with a 4 ohms speaker you will need to use a power supply circuit that will provide an output voltage from 8 up to 24 volts and if you want to use it with an 8 ohms speaker you will need a power supply circuit that will provide an output voltage from 8 up to 30 volts .
The maximum input voltage supported by this audio IC is around 32 volts .
As you can see in circuit diagrams this audio power amplifier require few external components even if is used in stereo or bridge mode .
For stereo mode connection , if you don’t find a dual potentiometer , you can use two separate potentiometers .  For the stereo configuration circuit you can use two 20 watts speaker , with an 4 ohms impedance ( each ) . The electrolytic capacitors  used for the project must be rated at least 25V ( a little more than the  applied voltage ) .