Hi there,
The graph is your battery life progression, and the bars below are just what they say and show that particular state of your phone with time.
For instance, from your graph, you know your phone has gone from 100 to around 45 percent in 13 hours and almost 6 minutes. From that, you can see that most of the time your mobile signal was crappy (browns and grays), with only a few times during that period with the signal being strong (green). Furthermore, the blue spots show that in that period, you used apps that polled for your location about 7 times. Also, you kept WiFi on for a few hours at first, then turned it off, then turned it back on at the end. Awake is the time your phone spent actually doing stuff, and the screen on is the times you actually turned your screen on. Usually, if the awake portion doesn't mostly match the Screen On portion, that means an app might be doing too much in the background. In your case, it doesn't seem out of the ordinary.
Additionally, if you tap on the graph, you'll get a list of apps and the battery percentage they've consumed. There you can see if an app is 'eating' through your battery more than it should. For instance, if you've streamed Netflix for two hours and check your battery status, the screen on and Netflix should be the top two 'consumers'. But if suddenly you see that, say, Facebook is above Netflix and you didn't even open Facebook, then that particular app is misbehaving and doing something that it shouldn't be doing (and I picked Facebook for the example because it's been very buggy lately and a lot of users, myself included, have reported sudden battery drains from it).