Who can tell me how to begin to understand conceptual photography, why it is needed in principle, what makes such photography special? And which photographers took the best conceptual photographs?

Well, first of all, I will try to tell you about what conceptual photography is. In general, conceptual photography is a special kind of art, where the main thing is not the beauty of the frame, but the idea it carries. You can see strange, unusual compositions, surreal scenes or even minimalism that makes you think. The main thing here is not the shooting technique, but what the photographer wants to tell the world. You can read more detailed information about conceptual photography here https://serhiifett.com/conceptual-photography-what-is-it/ .