Thanks for the query.
G is combined oral contraceptive pills
It contains 21 pills in one pack.
You have to start from the first day of the cycle. After 3 weeks the pack will over. Then you have to take one week gap. Usually in that week you will get periods.
Irrespective of the periods you have to start the new pack after that week gap.
For more details you can ask me through: http://www.healthcaremagic.com/doctors/dr-sree-gouri-sr/63429