I'm not convinced that reading instruction manuals will provide a guide to operating the most advanced devices, such as computers or phones.
Or even modern ovens, for example.
First, the manuals are often translated from Chinese by very inexpert translators, so barely make sense.
They also use jargon, rather than plain language.
And another factor is that as microcomputers get cheaper and there is consumer demand for things (from ovens to fridges and out to central heating controllers) to be 'smart' and to be connected so that they can be controlled remotely, they get more options.
Quite quickly, the option tree gets too complex for a clear instruction manual, so the manuals simply don't give complete coverage.
I can't, for example, imagine how anyone would write and publish a complete guide to using a modern laptop computer.
So the suggestion that one can read an instruction manual is not the whole story - unless we're dealing with something super-simple, such as an alarm clock. And even some of those are connected and have huge option trees (Time zones / alarms / Summertime adjustments / timers / connecting to online time servers and so on).
I think of myself as a techie, and very rarely use the instruction manual. That's not to say I know how to make everything work, but I can usually make a gadget do what I want it to do.
Most gadgets have some kind of commonality in the user interface: Menu buttons; up and down options; select options and so on.
Maybe part of it is lack of fear that I can damage the gadget by playing with the buttons
Another part is that I've handled a huge variety of gadgets and got them to work
An important part is understanding the symptoms that indicate failing batteries, or broken buttons or that there might be another control that is non-obvious (In which case, Google is my friend)
And the final part of the mix, as my partner would say is that technology knows it has to behave when I walk in the room.
She swears that something doesn't work, and she's done all kinds of things to fix it. When I do the exact same thing, it just works first time.
Of course I don't believe a word of that, but she swears that I give off the pheromones, or some kind of aura that causes the tech to behave. Until I walk out of the room, when it goes wrong again.... (removes tongue from cheek)