The first one is a simple track of A18-49 ratings and True ratings for each episode this season:
The idea here is a graphical representation of how well the True formula smooths out a show's trajectory as the season progresses. I kinda cherry-picked the most exciting one here, since the NFL lead-in made The Simpsons' raw ratings wildly volatile. Most of them are a lot more subtle.
Another note with this chart is that you can click on the legend at the bottom of the chart to make either of the tracks disappear. So if you don't believe in the True formula or something, it's easy to get a simple look at just the raw ratings, or vice versa.
The second one is the Sub-Demos Plus chart, which applies the A18-49+ methodology (100 * show average / average of all big four original non-sports series) to several different demos.
This creates a bunch of new paradigms where everything on the big four averages out to 100. That means these numbers can be judged using the same labels developed for A18-49+. (In other words, within each demo, you can say 125+ is a "hit", 200+ is a "megahit", etc.)
You can also compare these numbers against each other to see where a show is strongest in relative terms. For example, The Simpsons currently has a 1.87 A18-49 and a 1.63 A18-34 average. So you might say the show is stronger in A18-49. But in Plus terms, the A18-34 number is actually a lot stronger, since the A18-34 league average is less than two-thirds of the A18-49 one.
A quick disclaimer: with the possible exception of Viewers+, most of these numbers probably won't be used much more formally than this. The numbers shouldn't be seen as "official" since a lot of the sub-demo data is missing from my records. (You can see all the sub-demo league averages, as well as how many of the data points are missing in the Climate Center.) This is just meant as a general guide to visualizing how a show skews.
On the Vault pages, these charts are activated by buttons, which you can find below each show's True table. These are only available for the Sunday and Monday broadcast shows at this moment, but will be added to the other currently airing shows by the end of the week.