Been trying to sleep train for the last week. It hasn't been easy like we were told but I'm not…

Been trying to sleep train for the last week. It hasn't been easy like we were told but I'm not seeing too much progress. We set a scheduled bedtime, we follow a strict routine, and we put her to bed while she's sleepy but awake. She'll go to sleep on her own but she wakes up multiple times screaming her head off. After that she will put herself to sleep but will wake up every 15 minutes a couple of times before being fully awake. We started at 9pm and was told to up it. So we did 7:30 it there's no difference. Any suggestions? She's 4 months. The pediatrician has really pushed I start now and that there's no need for her to want to feed every couple of hour at night.