Keep positive and optimistic.
Have a sit around the table for a family team meeting. Up date regularly so that you can iron any difficulties as you experience them. Keep it businesslike.
Write out everything that needs doing daily, weekly and monthly.
Ask everyone to put their initials by the jobs they are going to do.
Explain they are no longer toddlers, it is not a hotel, as a parent it is your responsibility to teach them basic skills they will need for independence. It's also basic human skills to have social skills which are to be kind and hepful.
Every little thing, including internet access, watching tv and all the things they like to do will be your bargaining chip.
If they want to go to X then they have to finish YZ first and stick to it.
No need for shouting or histrionics.
Keep calm.
By having it all written out will make them realise how much you do and only the most selfish and spoilt would fail to see that it is not fair for all the household tasks to be dumped on one person.
It's all part of being a team. Make treats like going on holiday, trips or even sweets/chocolate as rewards for being kind and hepful.
They are old enough to know how to fill/empty the dishwasher and washing machine etc.
You will find giving them responsibilities gives them chance to feel proud of their achievements, no matter how small.
Good luck op 