@dinowish I think it's overwhelming at first glance, and then pretty easy to work out.
Each of the tracks (I think of them as subway lines) goes from top to bottom, getting harder. In general, it's unlikely that you'd be able to do an exercise without doing the earlier exercises along the track. The main purpose of this is simply to work out what the next exercise you should do once you've already mastered one.
So, for me, I copied the file (File -> Make a copy). I then started coloring in each track as far as I knew I already could do. See part of my chart here:
(Note, just select a section of track, and click the background color button, and you'll see you can color it the darker version of the custom color).
So on the first track I started coloring, which is part of the Front Horizontal Pull series, I can do Vertical Rows, Incline Rows, and Rows, so my next "stop" along the track is the Wide Row. Once I master that (which I'm taking to be 3x8 good form), I will try for the Archer Rows.
The different tracks split and join up because sometimes mastering an exercise opens up multiple new routes (e.g. from a Full Squat you can go onto to a Split Squat or a Cossack Squat or both), and sometimes an exercise will have multiple prerequisites (e.g. the Wall Headstand Pushup requires both a Handstand and a Decline Pike Pushup).
As for which tracks to do, I think ideally you'd be doing all of them. Of course some of them might not be part of your goals, e.g. handstands, so in that case, don't. This just helps you pick the next exercise from one you already know how to do.
(Pinging /@jessicabourne124 as well.)