There is a bit of inconsistency with the vertical lines.
For intros (or any section with no lyrics), the vertical lines depict one bar, however during lyrics, each chord is assumed to be a full bar, and only where there is a vertical line, does that indicate there is more than one chord to each bar.
I'll admit it can be one of the most confusing parts of the book.
I've just had a look at some TAB, and the sheet music for Walk of Life, and Justin has simplified it by halving the bar count. I.e. for every bar in the book, the sheet music has two bars.
So sticking with the book, for the Pre-chorus, you play each chord 4 times per bar, then when you get to the Chorus, there are two chords per bar, and you only play each chord twice.
For information, if you want to look at the sheet music, musicroom.com sells it digitally, but they let you preview the first page. So if you search the song, it gives you various options. The first option showing only Melody Line, Lyrics, and chords, shows the most of the song (actually, it shows the entire song!), however Justin has written the book with a capo on the 7th, meaning EA&B on the sheet music, become AD&E shapes played with a capo on the 7th, so as to avoid having to play a B (which you would normally play as an A shape barre, making it not very beginner friendly!)