To begin the meeting, access the same URL simply by a tutor and student.
Tutory is a web app for online tutor. It is able to video chat, share a screen, and draw on shared video/screen each other. And without creation any account, installation apps, and limits of time.
Don't worry! The meeting room accepts only two connections. Therefore, the outsiders can not eavesdrop. Moreover, a video connection is encrypted and peer-to-peer via no any servers. There is no risk that servers collect your personal data.