I successfully installed my rear bumper appliqué yesterday. My dealer gave me a copy of the Toyota information system instructions to work to.
In brief, after cleaning the area, I wetted the area and the appliqué with a soapy water solution, aligned it, and smoothed it out until the bubbles were gone with a 4" squeegee.
For the solution, I used 1/4 teaspoon Johnson's baby shampoo with 500 ml water in a spray bottle.
This black carbonfiber finish appliqué improves both the looks and functionality of my frost color iA.