Lift the wiper arm up, see that little bent-looking sideways pin on the anterior side? It's a horizontal bar opposite the wiper cowl, see it now? Right at the base of the arm where it connects to the spindle. Pull that. Lift arm. Done.
When you replace it, PLEASE rotate the arm 2 or 3 spines down and make your arms flush with the cowl. They look ridiculous sitting halfway up into the window.