If you want a quick guide then I will tell you here.
Step 1 : Get the kit. (pic is attached)
Step 2 : Draw a rough screw placing chart on white paper (it will help you to maintain left-right screws in position).
Step 3 : Switch off your phone and unscrew bottom screws by given tool.
Step 4 : Using suction cup remove the display and hold it on 90 degrees, not more than that as it is still connected.
Step 5 : Remove battery connectors and then remove display connectors so that you can completely remove the display.
Step 6 : Now remove battery but for that you have to pry sticky tape first. Once you find that just remove it like you are peeling a sticker.
Step 7 : After removing battery you have to remove old apple logo with pryer. Be careful and if you can't remove it use sharp edge to peel it off.
Step 8 : Place new logo in proper position. It'll completely fit in existing hole.
Step 9 :Now place the battery in its original position but don't reconnect it now.
Step 10 : On the underside of the screen there is a tiny cable coming from the top left of the earpiece. Carefully scrape away the tape on top of it so the three metal connectors are exposed.
Step 11 : Reconnect display to the respective connector.
Step 12 : Take one of the small sticky sponges from the light kit and add it to the very top of the skinny part of the light kit cable to form a T shape (perpendicular to the cable).
Step 13 : Now connect that part of the cable to the newly exposed connectors on the back of the screen.
Step 14 : Finally put extra sponge to connector and put electrical tape on it.
Step 15 : Reconnect battery. There will be a cable coming outside of battery. Don't worry that's circuit cable of apple logo. Just stick it on battery using electrical tape.
Step 16 : Put back display to it's position and slowly press on the sides to snap it back in position.
Step 17 : Put back those screws back in position and turn on your phone.
TaaDaa

You have successfully installed Apple light mod kit on your phone. Enjoy