Creating a 3 month old schedule

Hello!

First time mom here :) Any advice in how to create a sleep and nap time schedule for my 3 month old?

Currently we start bedtime around 7 or 8pm, she gets a bath every 2-3 days, I get her into her pjs and nurse her. Sometimes bedtime routine lasts 2 or 3 hours as she does not want to fall asleep or she does fall asleep and then wakes up as soon as I put her down. There are days she sleeps 6 hours the first part of the night and then every 3 hours, but there are other days she wakes up every 2-3 hours throughout the night. During the day she does not like to nap much and when she does, it’s only for about 30-45mins.

I know she needs a schedule and consistency, I just don’t know what to do to create that for her :( any help is greatly appreciated! Thank you!