I've purchased this item twice and I am having troubles securing it to the vehicle. It does not stay firmly to the vehicle perhaps I missing something I put the two in those square or rectangular spots but I'm not for sure if I'm supposed to push the upper part into the same spot.

Hi, we are sorry that you are having trouble with the installation. It is not possible to diagnose the issue from here. Our best suggestion is to seek professional installation. We apologize for any inconvenience.