This is not as obvious as it may sound. Adults often expect children to accomplish tasks for which there has not been adequate training. Parents may expect children to clean their rooms, but never teach them how. Children go into their messy rooms and feel overwhelmed.
Taking time for training means being very specific about your terms and expectations. Taking time for training does not mean children will ever do things as well as you would like. Improvement is a lifelong process.
Don’t expect children to know what to do without step-by-step training. What do you mean by clean?