ass backwards

Cliché: ass backwards
Explanation:
1. Doing the second part of a project or task before the first part.
see also [put the cart before the horse]
2. Doing something backwards.
3. Doing something in the wrong order.

Example 1: You asked for a raise before you did the work? That's ass backwards!
Example 2: Jane did an ass backwards job of writing the report. She'll have to write it again.
(Dirty English)