本末颠倒

本末顛倒
běnmòdiāndǎo

putting the cart before the horse

Wiktionary

Entry Composition

1 本末 běnmò
  1. the whole course of an event from beginning to end
  2. ins and outs
  3. the fundamental and the incidental
2 颠倒 diāndǎo
  1. to turn upside down
  2. to reverse
  3. back to front
  4. confused
  5. deranged
  6. crazy