One group I played with some years ago, back in 2nd edition, had, as part of their character generation/background process, an explanation of what event caused that character to gain the experience points that pushed them from 0th level to 1st level.
For example the Ranger I played in that campaign was a country farmhand who grabbed an axe and successfully killed a couple of desperate goblin raiders who came to plunder the fields.
I really liked this idea, and am mulling using it again in a 5e campaign I've got planned for the autumn. But I wondered whether there was any official rules material to give rigour to this process.
So: is there anything in 5e rules and supplements that describes the process by which an ordinary 0th level person becomes a 1st level anything?
(This was inspired by this question, which I thought was asking the same thing)