There are four videos to look at this time. Mine is the first, and the author has three quick ones. To further help you, play with INTERACTIVE FIGURE 1, INTERACTIVE FIGURE 2, watch this SCREENCAST, and work on the TUTORIAL.
Source: (C) 2016, Pearson
Source: (c) 2016, Pearson
Source: (c) 2016, Pearson
Source: (c) 2016, Pearson