Teach an old dog new tricks?

Hey everyone. I am what is referred to as an older citizen.  I have dabbled in auto repairs over the years, but admittedly......I am from the era of push starting my truck, cleaning up mechanical points with my wife's nail file, and setting point gaps with a matchbook cover.  I have my hands on a OBDII bidirectional tool and I have a couple of vehicles that have engine performance issues.  I would like to ask for everyone's advice on how to use the premium access here and the Ebook which I also purchased.  Tons of this is Greek to me, so if there is a particular order or method that has worked well for others, please let me know.

Welcome to the community.
Just like anything else, it can seem like information overload at first. I found the most value in following the classroom lectures videos in order to really cement the foundational knowledge. Then the case studies make more sense. At least that's how it worked for me.

Depending on your electrical background, you may want to check out some of the Basic Electrical Concepts  videos, early on. They may help understand some of the classroom lectures a little better. 

As Noah suggested, I too recommend that you start with Chapter 1 and work your way through the classes. In each Chapter menu, after the classroom lectures, there are case study videos down at the bottom that show real-world scenarios that will help understand how and when to apply the lessons at hand. Sometimes, after watching the case study videos, going back to watch the classroom lectures, again, really helps the subject matter sink in. 

If you ever have any questions, just ask.   

Welcome! Looking forward to hearing from you in the comments of the classes.
I agree with Noah and Chad about where to start. Also check out my introduction and navigation video on the SD Premium home page when you are not logged in. It will disappear when you are logged in (that is something I need to change)