Hello I have tried this before. I started it with one male in a 10 gl. Then I got 3 females and a load of plants of various sizes and shapes on the same day. And I took the male out while I planted the tank then put him in for about 20 mins so he can establish his territory, then I put the three females in at the same time (after floating the cups for 15mins).
The reason you want more than just a couple females is so that when the male starts to chase one female he will spot another one and start chasing her. So no one female is picked on more than the other. And also the females themselves establish their own hierarchy.
They were fine for about 2+ weeks then one female started to nip at the males fins and I wanted him to stay pretty (who wouldn't want their male betta to stay pretty lol) So I separated them all and got another 10 gl tank to make as a sorority for my lovely females, which is working perfectly fine. And I separated the first 10gl tank into 3 parts and got two more male bettas. And my separated male betta tank looks and functions beautifully. Just thought I'd put in my two cents :) best of luck to you.