the guy in the video does it kinda right its hard to explain. but please spend the $30 and buy a proper heat gun, i have done 10 whole car wraps, countless mobile phones, 2 motorbikes, Dont use a card on the edges use your finger you will notice if there are any creases in the vinyl. when you're happy with how it is sitting you have to heat the edges up to above 90 degrees C to activate the glue otherwise in a couple of weeks or months it will start to lift.
here is a photo of my car https://fbcdn-sphotos-d-a.akamaihd.n...11182756_n.jpg