User blog comment:Thrycius/Zheiro and The Moonlight Sculptor: Chapter 11/@comment-26328778-20150712062605/@comment-25002135-20150712154800

It was less of a lesson and more of a demonstration of summoning. If you recall all the way back in chapter 4, when they received their first gem Zheiro asked about it out of curiousity, and Thrycius said that he would show Zheiro how summoners use them, and I'm pretty sure you already know he kept his word.

Since it was a demonstration rather than a lesson, Thrycius threw in tons of extra (albeit useless) things for the sake of entertainment (like the chant), which would not be helpful at all if you were trying to learn how to summon for the first time.