Is it enough if I have one PC?
It is possible to participate in the lesson with one PC, but considering to use the textbook on hand, it is better to use two devices such as PC and tablet or PC and mobile phone. You can participate in the lesson with the tablet but the video will be off while you are watching PDF data of your textbook in the tablet. ( You can listen to the teacher and your classmates talking but you can't see them.) Also, it is not necessary to prepare microphone and camera if they are installed in your PC but we recommend to use headset or earphone with microphone to provide the better environment.