This is a Class A amplifier with a preamp stage.
The input signal is approximately 0.5V RMS, which is typical for audio outputs from phones or laptops.
The output signal is around 1.5V RMS, but can be configured for higher output levels.
A 4-ohm resistor is used at the output to simulate a speaker load.
🔎 For a full explanation, search "ElectroInnovate" on YouTube
