the.com/cart before the horse

means To reverse the natural or logical order of things — doing or prioritizing what should come second before what should come first.

from A simple, sturdy image rather than a single traceable coinage: a horse pulls a cart, so putting the cart in front of the horse makes the whole rig pointless — nothing can move, or it moves badly. Versions of this image appear in English going back centuries, and similar logic-of-order proverbs show up in other European languages too, which suggests it's one of those metaphors so obvious from everyday farm life that it got reinvented independently rather than borrowed from one single source.