Question, I want to get into more lower level programs like compositors or docker daemon or kernels (I do realize they all are different things) but I find tech

Question, I want to get into more lower level programs like compositors or docker daemon or kernels (I do realize they all are different things) but I find tech behind them so intimidating and don't know where to get started. Do you have any advice where I can learn them? I'm about to grad next year