I call it AC because the preamps are in class A mode and the power amp is in class C mode. At the input there should be the antenna plus the tank circuit at the given frequency. You can use the output to drive a demodulation stage and run it through a speaker. So to make this into an AM receiver just add the proper LC tank circuit at the input. It typically consists of a large inductor of 60-70turns around a large ferrite rod that also acts as an antenna and to add a simple envelope detector at the output (a single diode and a capacitor) and the simplest current amplifier you can get your hands at to drive the speaker or just use an old high impedance speaker from an old telephone without any need for amplifiers. If youbintend to use it as a retranslator to boost a weak signal the output is 500mW so a few KM could be covered
