The missed put warrant I should have bought

Just when I just started learning about structured warrants, hindside should have bought a Hong Kong index put warrant to bet on the downside of Hang Seng. 

The fall in Hang Seng was due to fears China might arrest Hong Kong based company CEOs that sympathizes with Hong Kong protests on the extradition bill.

Traders profit from put warrants when the underlying indice/stock goes down.