you can apply it various methods personally I use the tape & peel / tear an inch off method. Basically you tape the side art on and then you can make sure it's level / and rip actually tear the backing about 1-2'' and slowly peel it downwards while taking off the tape while your going down. I usually use a ruler / yard stick to flatten it while going down. If you get any air bubbles you can usually squeeze them out with the yard stick.
here is a video: