Short answer from my experience: you don’t 😂
I've got a 2.5y old and a 15 week old and I'm yet to work out how to keep the house clean so I just try to keep on top of the basics unless I get some free time when eldest is at nursery and the youngest is settled enough for me to leave her to clean properly 😂
I’ve 3 under 4 and I can honestly say it’s the hardest thing xx