Can I Take Mononessa Immediately To Regulate My Period?

I am going to start taking Mononessa to regulate my period. The only problem is is when I read the directions given to me it only says to take it on day 1 or the Sunday after your period starts but this deals with how to take it if your taking it for the birth control purpose. Do I have to follow those directions even though I do not know when my next period will start? Can I start taking the pills right now?