So sorry to hear people will stoop to this level.
Holes surrounding the cavity where the emblem goes suggest to me there are plastic tabs on the emblem which latch it into place.
The tab you received with the emblem is likely a locking tab that must be inserted into the emblem and is locked into place or inserted before and turned to lock from behind.
If you have a dealer nearby, you might receive helpful advice for something this relatively simple for free. Can't hurt to try, or you could find another car the same year and ask the owner if you can look behind the grill with a mirror to see how it is affixed. Most of the installation looks to be simple press fit plastic latches on the emblem that insert into the main grill.Looking at the back of the emblem should help.