What is saving?
Putting money somewhere safe where the amount does not fall. The return is small and the point is not the return. The point is that the number will still be there.
Saving is for anything you will need within a few years: the fund, the tax bill, the replacement vehicle, the wedding.
What is investing?
Putting money into something that can grow and can also fall, in exchange for the possibility of being worth more later.
The rise and fall is not a malfunction. It is the mechanism. The chance of more is paid for by accepting less at times of somebody else's choosing.
What actually decides which?
When you need the money.
Needed within three years, it should be saved, because there is no way to guarantee a particular value on a particular date.
Not needed for ten years or more, saving alone means watching it lose purchasing power quietly while feeling responsible.
That is the whole test. Not confidence, not knowledge, not what somebody at work is doing.
What comes first?
The order that keeps men out of trouble is unglamorous. A month of costs set aside. Expensive debt dealt with. Then investing, steadily, into something you understand and would not panic out of.
A man investing while carrying high interest debt is paying more to borrow than he can reasonably expect to earn, which is the arithmetic version of running to stand still.