Step 1: Clean the Tail Light.

Clean the surface of the Tail light with soap and water to ensure all debris are removed from the surface of the Tail Light. 

Step 2: Remove the Vinyl from the protective sheet.

Carefully remove the Overlay from the sheet and spray the overlay's adhesive side with Soap

And Water. 
The Soap and Water will prevent the Overlay's adhesive from sticking while you apply it the Tail Light. 

Step 3: Spray and Apply the Overlay on the Tail Light.

Carefully apply/align the Overlay on the Tail Light and smooth out as much crease as possible by using your fingers. 
Use the vinyl squeegee to push out all the soapy water on the front face of the Tail Light. The more soapy water you push out the less bubbling there will be. 
Note: Make sure the crease are evenly distributed on the Overlay, therefore you can easily smooth it out with a heat Gun and Squeegee.

 Step 4: Fold the Side inward.

Carefully pull and fold the side inward. If necessary, use the hair dryer to soften up the vinyl and squeegee out all the crease.

 Step 5: Heat, Pull, Stretch.

Heat up the crease and begin stretching and pulling the vinyl. You will notice the crease 
begin to smooth out. Stretch it and align the edges. Don't be alarm if you over stretch it. It is okay. 
The excess vinyl can be easily cut
Note: Do not over heat. Overheating will cause bubbling. Patience is key here. Take your time!! Don't rush

Step 6: Trim the edges (Optional).

Heat up the excess vinyl (heating up the vinyl will soften it and makes it easy to trim) and trim
Note: Don't worry if you over stretch the vinyl. Any excess vinyl protruding 
can be easily removed using a brand new exacto knife.

Step 7: Repeat on the other side.