Its difficult to explain but I have just done the same with my G60. There are expandable fingers that push together to enter the square hole, then expand back out again once they are home. They are a tight fit and it takes alot of grunting to get each one home. You then should have two plastic wedges to bang into place into the outer most 'fingers' to stop them collapsing and disengaging from the metal frame. You may get away with a couple being damaged, but when I removed the front bumper from my car, the bumper cover just came of from the frame as it was so badly fitted by the last owner. It does not bear thinking about what could have happened if the bumper came off at high speed which would have been a real possibility.