Here's how I installed my plate. No drilling needed on car or bracket.
Start by turning the bracket upside down and feed a series of four 8" zip ties through the top pair of mounting holes. You can figure the rest by the series of pictures.
The final step is one more strap to link the first two you fed through the mount and a small strip of plastic tubing to cushion the bracket against the bottom fascia or anywhere the bracket may rub.