Ask HN: How to self-learn to build real things (ie: dishwasher)?

I've always started by consulting experts, i.e. people who already know how to do it and can instruct you. Want to learn how to build engines...? Try working with a master mechanic for a while... this leans on the apprenticeship principle, for a reason, it's a tried and true way to learn.

If you can't get that ( or as a supplement to the above ), try reverse engineering something, for example disassemble a dishwasher and study how/why each part or piece makes up the whole, until you understand it completely. Governments and competitive companies sometimes employ this tactic to gain knowledge in areas where they are deficient or far behind.

When all else fails and you can't learn under an expert and have no access to the products or tools, you could always fall back on internet videos, online classes, or even book learning.

Good luck!