What I would do (and have done ) .
First start with a proper clean with each kid in their room. Absolutely everything gets looked at and sorted and declutter as much as possible. Bring bin bags and they have to help. They decide what to keep and what goes, make piles. You do x job, they can take all plates down and wash/put in dishwasher. Everything needs putting away/will have a place to go. If they have too much crap, some of the crap must go or nothing new is bought. Once it’s all sorted and clean and tidy, they are responsible for the upkeep. No, they can’t go out until their room is tidy. You’re hoovering (for example) on Tuesdays and Thursdays, the floor needs to be empty. If it isn’t you’re either bin bagging everything on the floor OR dumping it in their bed.If shit gets hoovered up, though titties. Your job needs doing, you won’t skip it because they haven’t done theirs or do theirs for them instead. Crockery down every morning, or they’re not allowed plates upstairs. Can’t find shit? Though. It’s wherever you put it. Invest in storage if need be and make sure they know where everything should go.
A mix of natural consequences and parental consequences, with clear , set rules.
Natural: can’t find shit, stuff gets broken , doesn’t get replaced, no I’m not washing your favourite tshirt at 11 pm because you need it in the morning, run out of clean whatever , and so on, you don’t have time to do x because you have to do y because they haven’t done it/left it too late.
Actual consequences: didn’t follow the rules, you’re not going out until you do, no pocket money, no wifi , no lifts.
Ask them down to put their crap away , everytime. If they kick off, one warning and then go back to actual consequences. Don’t engage in arguments and life is sooo unfair and you’re the worst mother ever and I haaaate you! “Yeah, I know .. now put your plates away”. Ignore the whinging and whining.
Basically you need to make it harder/more inconvenient to not do it in the first place.
It will take time, it will be exhausting and you’ll be tempted to give in because it’s easier/quicker to do it yourself, but they will learn eventually.
Most importantly, make it clear , you’re a family, you work together, you help each other out. Your goal is to raise functional humans .