The students need to have complete faith on the instructor. Every teacher who is teaching through an online platform is aware of its limitations. They have already worked out the best way to guide and instruct the students accordingly.
Yoga instructor will advise the students to get the right equipment - for example, a Yoga strap. It helps to perform difficult stretches and also hold a difficult posture for a longer duration as a beginner. For a new students, they will start with very basic postures, and work on the strength and agility of the body. Gradually, they will lead the students to perform more advanced postures