ELI5 how does CPU know what to do?

r/

I understand that programm is compiled to a list of binary numbers. I know that they got loaded into memory. But what’s next? Ok, maybe CPU has a register of some kind to store the adress of command so it could be loaded into processor. But how does CPU know which opcode is which? how it deffers 0xff from 0xfe? How some commands start a pretty complicated list of actions eg. lda