You need to take off the side blinkers by using a screw driver with a towel around it so you do not scratch the paint and pry the lights off. then tape the lights to the inside of the fender so the don't bounce around in hard driving. After that take the paper off the back of the covers and carefilly press them against the blinker spaces.
I wouldn't use a screwdirver at all. There is always the possibility of it tearing through the towel or cloth you are using. I'd simply get a firm grip and pull upward. It's an "up and out" motion that is needed. A good thing to use is one of those rubber grip jar openers. Try not to use a screwdriver in fear of scratching the paint. That's what I did to replace the orange markers with clear ones.