How to use the puck Adaring?

I am 6 weeks after giving birth, the doctor on the follow-up visit instructed me to use adaring without having to wait for a period- after the previous pregnancy I did not get menstruation because I became pregnant. After this pregnancy, bleeding has not yet occurred. I understand that by the time the period comes, I should be securing an additional condom, but what should I do to take full advantage of the benefits of the puck as menstruation appears? On the first day of menstruation put on a new ring?