D316 IT Foundations

I'm currently in D316 IT Foundations for CompTIA A+ core 1 at WGU and have plenty of training material, but that is the issue. It's just so much information I'm not exactly sure what I need to retain and study. I've also been watching Jason Dion and Professor Messer videos but it's so much. Any advice on where to start or what specifically to pay attention to retain?

P.S. I'm just going to go out on a limb and assume that core 2 is the same, again anything helps. Thanks in advance.