I laid out the textbook I used when studying for the Computer Literacy Level 2 certification and taught them 'from scratch.'
"No, don't do that, Vicente! Don't break it! That's the power button!"
"Since the computer looks hot, how about cleaning it with water...? Think about it, Eleanor. What would happen if you cut open a person's stomach and poured cold water when they're hot?
...No. It might come back even if it breaks, but sparks could be dangerous."
"You want to cut it open and examine its structure? That's good curiosity, but it would be difficult to understand even if you saw it.
This is a machine processed so minutely that it's invisible to the human eye... Hey, don't touch it! You'll get hurt!"
So, 'from scratch' means things like this.
How to hold a mouse.
The purpose of a keyboard.
The meaning of function keys.
The meaning of a desktop and the use of shortcut icons.
And various other things...