New to video conferencing / streaming

Hi, during the times of COVID-19, I would like to offer people from all around the world free yoga classes using your program. To do this, I’m wondering what my best option is so as I can start teaching Tuesday night. I’m not sure how many participants I’ll get, but I am hoping for quite a significant number. How am I best to do this? Streaming or conferencing? What is the difference? How do you push to YouTube? Can I make them password protected? I understand you can only see/hear 8 participants at a time, I’m wondering if my screen will then automatically switch to others within my teaching so I can see more people without having to physically change it? I need directions please and sorry to ask at a bad time.