Low poly high poly baking workflow

Hi,

im learning how to make game assets that will eventually be compiled together in unreal5. I'm creating models in maya then bringing them into Zbrush to add detail. But that's as far as I've gotten. Im quite good at substance painter, however the workflow confuses me, I want high detail on my models but dont want to slow my project down in unreal with high polys. 

Can anyone tell me the correct workflow from maya to Zbrush to substance to unreal? I can do each part but can't figure out how to connect them together. I'm blurry on baking and using the low poly model as final but not knowing how to extract the high poly maps from Zbrush etc etc. I'm so confused. HELP!