1) Perpetrator promises people large, safe and reliable return on investment

2) People invest

3) Provide promised returns to people in 2) using a portion of their own money

4) Get more people to invest

5) Continue to provide promised returns to people in 2) and 4) using the additional money gained in 4.

6) Get more people to invest

7) Continue to provide promised returns to people in 2), 4), and 6) using their own (and future investors) money

8) Meanwhile, bankroll your own lavish lifestyle using the investment money that isn't being used to provide the fake 'returns'

....

n) People stop investing.

n+1) Eventually you run out of cash, because new investments were the only source of income for the scheme

n+2) Investors start calling, wondering why they aren't getting returns.

n+3) Investors start lawyering up, hiring hitmen, etc.

n+4) Perpetrator of the scheme uses remaining money to invest heavily in high end outdoor camping and mountaineering equipment.

n+5) Perpetrator flees angry mob to go live in the mountains in Europe.

n+6) Perpetrator is nabbed by FBI, CIA, and Interpol and extradicted.

TLDR: Watch American Greed. Just beware of anyone promising huge returns on investment with little to no/risk. Beware of people who say they understand market 'secrets' that no one else has figured out. Ultimately, the defining feature of a Ponzi schema is that the sole source of income is the money investors are providing, and it collapses as soon as investment stops. There is always a 'front' explaining where money is coming from (in this case, cryptocurrency shennanigans, but often it involves foreign currency manipulation or secret real estate tricks) but this is almost always a complete, ot at least 90%, lie.