A few goals, but the main one is to put the pedal spindle under or slightly behind your metatarsal joints but depending on float in you pedals it's also good to get them rotationally correct and if you have particular stance width issues it's good to get them laterally correct. The latter two (rotation and lateral width) are coupled in Look style cleats as opposed to something like Speedplays which separate those adjustments.
Good info on cleat setup here:
Maybe Hogg has discovered some new field effect (after all, there is an e- field around a human body and those bracelets are dielectrics.......) and will some day be as highly regarded in field theory as James Maxwell. Maybe not is also a possible outcome.
the delta cleat, like look's and shimano's, are easy to reinstall for cleat replacement just by watching carefully the position of each of the three bolts on each shoe, but for the first installation you need a small bit of patience to do it correctly,