Vitex advice.

I've posted on here that I wanted something to help with fertility as before i got pregnant with my son my periods were crazy irregular. I could go 4 or 5 months with no period. Anyways i decided to take vitex as I've heard many positive stories about it regulating. Now my next question is how do you take it? Like the bottle says one pill 2 or 3 times a day since they are only 400mg and i should be taking 900-1200,which i read that online. Any advice helps.