If you say that someone is putting the cart before the horse, you mean that they are doing things in the wrong order.

e.g., The government put the cart before the horse by investing heavily before making major reforms.

He put the cart before the horse by signing the contract before reading the fine print.

Lucy hasn’t invited you to the reception yet, so don’t put the cart before the horse and buy an expensive dress.

Tradução: Pôr o carro na frente dos bois.