A lucky apprentice in any trade will spend at least a year carrying garbage, fetching tools, and buying coffee.
An unlucky one will receive tutelage.
You can spot the unlucky situations. One person is doing the work, the other is supposed to be listening to what the first is saying and watching what’s going on. But one of these people doesn’t have a clue, normally – how to teach, that is.

I am most familiar with articulate explanations such as this: “You take this thing and shove that end in there and hold that with your foot on the floor and pull back.” (I’ve removed the colourful language.) Eventually, the unlucky befuddled kid will get his chance and, because of a mixture of genuine ignorance and appropriate fake confidence, will probably do it right but not actually have any idea what it is that he’s doing.
The most helpful bit of advice I got long ago was while putting a lock in a door. The door had no prep, so I had drilled the holes and was about to chisel in the latch. My “teacher” Pete saw what I was doing and said, “Don’t hold the chisel like an idiot.” (Colourful language removed)
I spent a minute or so trying to figure out what was so wrong about how I was holding the chisel. I could see no problem, so I resumed what I was doing and immediately chipped a large chunk out of the edge of the door.
Pete showed me how to glue the piece back in and hide the repair. (It’s not that complicated: you put a piece of painter’s tape over it and hope no one notices.)

So, I always endeavour to not hold my chisel like an idiot. Lucky for me, I spent a lot of time sweeping that year.
Not so much, one unlucky ductwork installer I knew at the time. He had been shown how to strap the short pieces of duct together and hang it. Billowing great bravado and confidence, he gladly took the assigned task of putting a main run up in a hallway using a hand-powered lift, a ladder, his trusty 9.6 volt drill, and his wits. He was not very fast but he was getting it done – until it became apparent that no one told him that 1/2 inch self drilling sheet metal screws were not such a good choice for attaching metal straps to wooden rafters to hold up three-foot wide duct. It was a straw-that-broke-the-camel’s-back situation.
Oddly enough, the duct itself was undamaged. But it was a little useless installed there on the floor.
I can’t begin to describe the endless stream of words of encouragement he heard that day. Or the day after. Or for months after that.
When you’re young, you want to show how much you know. The mistake teachers and trainers make is encouraging people who know little to show exactly how little they know.
But the lucky apprentice will not have such terrible things happen to him. It’s difficult to ruin something by sweeping up sawdust. It’s hard to incorrectly install the coffee in someone’s hand. And he will get the opportunity to be by his master’s side and learn mostly by subliminal programming.

Soon enough, not only are you doing what he does, but in exactly the same way, using the same foul language to fuel your activity, laughing at the same jokes, ridiculing the same things.
And of course there is learning by example. Pete once wanted my help with a weekend project to paint a stairwell and hallway in an apartment building. I was given the task of carrying paint up the stair and then I had to paint, with a brush, the stair risers and baseboard.
Meanwhile, Pete was painting the walls with a roller. But there came a point where he could not reach the wall above the actual stairs so we went out in search of something to stand on.
The fence next to the building was chain but had been wood at some point. There was a large stack of painted fence boards between the side of the building and the newer fence. Pete grabbed several of these with a gruff “This’ll do” and carried them back into the building. I watched while he pried out and straightened some of the fairly rusty nails. He arranged the boards in a house-of-cards configuration and nailed them together. In the end, he had a makeshift platform extending out from the hallways floor over the stairs. It was almost level.

There is perhaps a little magic involved when you put a 200 pound man on rotten 3/4 inch boards and they don’t break. Pete casually took his roller and tray and walked out onto the platform and painted the walls. It bounced a little with every move he made but it didn’t break. It was a testament to ingenuity.
But then it slid off the top step and pitched everything down the stairs.

Luckily, the paint tray was almost empty so there wasn’t much to clean up. The wood was also easy to move because the jolt had caused it to collapse on a molecular level and almost no pieces were left over a few inches long. Pete was laughing and sitting on the steps while I shoved everything out the door into the parking lot.

“At least I got it all painted,” he said.

“At least you’re not dead,” I said.