You can establish some basic house rules, but you have to keep at them all the time and be consistent. Don't let them get away with breaking the house rules.
No running indoors.
No jumping on furniture.
No throwing.
No horseplay.
No drenching the bathroom during bathtime.
Crayons and markers, etc, stay in one room.
Indoor voices always - no shouting.
This teaches awareness of behaviour and volume and that different behaviour is appropriate in different places.
Kids must say please and thank you if they want something from you.
No helping themselves from the fridge or cupboards or fruit bowl.
The reason to ask is to establish who is in charge. They can progress to helping themselves when they're older.
Beds should be made each morning.
Clothes for school should be laid out each night.
Before bedtime, they can help you pick up their toys and books, etc for half an hour.
All of this can be done cheerfully, with hugs and high fives when the job is done. They will gain a sense of appreciation for order, neatness, and working together, and will start to take pride in their home.
Your children need you to step up and take charge. It seems from your posts that you're leaving an abusive situation (well done!) and it's natural for children to be affected by that. They've probably lived with a person who made them frightened and anxious. Now you need to establish a home life for them that is ordered and calm and secure, and home will be somewhere they will feel safe.
Yes, it's a big ask, and you yourself are dealing with the after effects of trauma - the feelings of being useless and incompetent and the stress are all responses to trauma - so make sure you develop little rituals for yourself that help you feel less stressed.
When they've gone to bed, finish cleaning up and light a candle, rub moisturiser onto your hands or feet, or listen to a meditation app. Don't get sucked into having a glass of wine to unwind. That's a slippery slope for many women. Remind yourself how far you've come, and give yourself credit.