Honestly, those apps scare me a bit. I tried one for a dishwasher fix and the steps were totally wrong for my model. It's fine for a loose screw, but anything with wiring or a serious leak is too risky. You need the full factory manual to know what you're really dealing with. I'd hate for someone to get in over their head because an app gave bad info.
Saw an article last week about people suing one of those big repair app companies. The claims were exactly that, wrong wiring diagrams that fried control boards. Makes you wonder how they even get their info, right? Rushed crowdsourced stuff maybe. Nancy's spot on about needing the real manual for anything beyond basic stuff.
That lawsuit is a perfect example of why I stick to paper manuals. Some intern probably copied the wrong diagram from a forum post. It's scary to think how many boards they've cooked.