If you've never installed an emblem, here's a quickie instruction:
Get a little wax & grease remover (aka lighter fluid), and clean the area very well. Make sure there is no glue residue left over from the previous emblem's double-sided tape (what is pictured in the image)... Clean area well with WGR on clean rag, let sit to dry well for about 10 minutes.
If the emblem you bought does not have a double-sided tape type substance die-cut to the emblem's shape, you can get some 3M 2x tape from an auto parts store (will be black with a red peel-off)... If your emblem is chromed on the back, take a razor and scrape off the chrome plating. This will make sure the tape sticks to the plastic itself and not the chrome, which is known to bubble, flake, and/or otherwise fail. Apply the tape to the back of the emblem and use a good quality sharp razor blade of any kind to cut the tape to fit (following the emblem's contour about 1/8" in from the edge is your best bet, and usually there will be a small ridge along the edge which makes for a GREAT cutting guide). Cut to shape, peel tape excess off, and carefully install onto car. Once you set the 3M 2x tape it's on there for good unless you have the necessary equipment and skill to peel that bad boy up. The 3M emblem tape is serious business, which is why I use it to hold my electronics down in my off-road RC racers. Seriously, you have one shot at getting it straight, so eyeball the hell out of it until you feel it's straight enough to press on permanently.
OR:
Get ahold of this:
1. 1min body epoxy (Valvoline Pliogrip(R)), epoxy gun (like a caulking gun, but with two plungers that work in tandem)
2. Urethane bumper glazing putty (it exists, and it's awesome!)
3. 80 grit, 320 grit, 600 grit sticky-back for DA.
4. DA (Double-action) sander.
5. Primer, paint by code, paint gun, paint booth, professional bodyworker (optional).
and SHAVE that bad mammer-jammer!

(yes, it IS still 1972!)
Hope this helped!
- CK