just up the back of the car, theres this huge plastic thing, take it off, like 3 clips and 4 bolts, it takes some wiggling around, but it'll come off.. it'll expose 2 bolts.. take one out, put one end of the bar in, and do on the other side, then u gotta tighten them both down alternating sides till their both firm
i left my "diffuser" (big plastic piece) off, i put the clips in, and i've been fine but if u put the diffuser back, you'll never see the bar