How to give a first-class massage

First-class massage is started by two round buttons on the armrest of the seat. According to the relevant information, I know that there are two round buttons on the armrest of the first-class seat. Press one of them, the body leans back, the backrest leans back, and the other one can be massaged. Train seats are divided into first-class seats and second-class seats. The first-class seat is a business seat, which has more space than the second-class seat.