Summary
Audio is a critically important part of a video. Even though it's often treated as less important by an editor who's more aligned with the video side of things, bad audio will ruin a good video every time. The standard approach, to buy good equipment and use it properly, will work most of the time, but however careful you are, you'll need to be able to turn down that uncontrollable air conditioner or bird, level out that person who spoke at an inconsistent volume, and find a way to deal with the microphone that's rubbing on that jacket or suffering electronic interference.
Now that you know how to add a voiceover, control its volume, add effects, and manage Roles, those tasks are much easier. Because you also understand how Roles can be applied, more complex tasks should be easier too. With the audio taken care of, at least for now, it's time to look at the world of titling and captioning.