Okay, so the basic idea is that you're defining pre-set modes for use in combat, When you select a mode, your Chanter will use each phrase one after another in a loop. So, a very basic set up is to have Mode A be a single phrase. Your Chanter will use that phrase over and over until you select a different mode. Alternatively, you could have Mode B alternate between two phrases by going Phrase 1, Phrase 2. So you'll use the first phrase, then the second, then the first, then the second, and so-forth. After X amount of phrases, you can use your invocation. Honestly, I'm not sold on multiple phrases as a viable strategy, but I've only used one briefly, and he was a first level hire.