This piece for Malachain collects the advice that holds up in practice.
A small, regular allowance teaches more about money than any lecture. Pay it on the same day each week, in cash for younger children, and let them decide what to do with it, including making mistakes. The moment a child saves for three weeks and buys something they chose themselves is worth more than any amount of advice.
Introduce three jars or envelopes for spending, saving and giving, and talk about the choices without steering them too much. As they grow, move to a basic bank account and show them a simple budget for a family outing. Children who have handled money from the age of six or seven arrive at adulthood with habits that many adults are still trying to learn.
The most useful step is usually the first one. Pick a single suggestion, try it for a couple of weeks, and then decide whether it is worth keeping. Small, steady improvements last longer than ambitious plans that are hard to maintain once everyday life gets busy again.
It also helps to talk the subject through with friends or colleagues who have tried something similar. Their experience points out the details that guides leave out: how long things really take, which costs were unexpected, and which shortcuts turned out to be a mistake.
There is more to learn on this subject, and the linked website goes into greater depth. Treat this article as an introduction rather than the final word, and check any important decision against up-to-date, reliable sources before relying on it.