Is it required for the teacher to contact the student?

Yes, you should always contact the student who books a lesson with you, regardless of whether they contact you first. 

To contact the student, you can use the platform's messenger, which can be accessed from either the lesson card on the Lesson Screen or in the Dashboard. To start the conversation with the student, just click the double-speech-bubble button at the right section of the card. This action will also add the student to the messenger, and you will, subsequently, be able to see the full conversation thread in the messenger.

You can also find the same double-speech-bubble button on the right of the student's card in the Students Screen.

For recommended content of your first message to the student, please refer to this article.