Clean the device, remove dust, dirt.
Spray a little bit of gel on your fingers to not leave any fingerprints. Then apply it on the back of the protection. (5-6 times)
Position your protection on your device. Use the home button, earphone, cameras to align the protection. If the protection is not aligned properly, you can peel it off, add more of the installation gel and reapply.
Take the squegee and use it to push the gel outside. Start form the middle out to the edge.
Look closely for bubbles or any large pocket of gel and push them out.
Curved areas require a little bit of extra effort to remove the gel.
After the installation process you will probably noticed some small amount of cloudiness or haziness that will evaportae within few hours.