trinessa

So I have a question about trinessa. I was prescribed the pill and my doctor told me I could start taking it today but if I got my period before the 4th week pills the "placebo" pills, to just throw the rest away. Did he mean to just not take the rest of the hormone ones and just take the placebos?
He also told me I could just start taking them when I get my period but does that mean I take the hormones right when my period starts ? I'm a little confused