don john paid borachio to do what?

Don John hatches an evil plan to ruin the marriage between Claudio and Hero. Don John pays Borachio 1000 ducats to ascend Hero's bedchambers and spend some "loving" time with his girlfriend Margaret (also Hero's gentlewoman). The set-up means that Claudio would witness sounds from Hero's bedchambers, in particular Brachio calling Margaret "Hero" but not clearly see who was up there. This of course is enough evidence for Claudio as to Hero’s infidelity. Being an almost cuckold, (apparently this is the worst thing in the world for a man back then) Claudio decides to humiliate Hero during their vows.