As an introduction, Professor Tom Krause explains how the vocal chords work. The student has a cold, so in this case it is more convenient not to sing in a very technical way, but rather to sing as speaking and smiling.
Throughout this aria from Purcell's Oedipus, they work on phonetic issues, vocalic and English pronunciation. For the high notes, it is recommended "using" the whole body.
Afterwards, Professor Krause makes some suggestions about how to sing in a better way the piano notes: she should not narrow the throat in the attack on these notes and support them more.
To finish, the professor also makes some indications about breathing, support and body connection.