In early learning repetition and learning by example are important. To carry your lego story a step further - You build 90% of the Falcon while your kid watches. But then you only build 70-80 percent on your next lego project, and after 3 or 4 more projects your kid is mostly going solo with the occasional question.
You instinct about starting with a simpler kit is also valid. Showing kids the most complex thing at the beginning is a good way to intimidate them to where they have no interest.
Same for homework. Sometimes I feel like I'm spoon-feeding my kids the whole assignment. But they learn a little even when we do that. Some evenings they do very well on their own and I'm just quality checking on spelling and handwriting.