This guide was very good and I was able to replace the screen successfully.

For the parts where they suggest heating, I used a couple of those reusable hand heaters.

I replaced just the screen so had to remove the home button, front-facing camera, etc., which is part of a different guide. The most difficult part about the reassembly was getting the mic and light sensor to seat in the housings. I suggest using LOTS of light and working from the top of the phone with the home button furthest away. Seat the mic/light sensor pieces and hold them in place with the spudger. Carefully slide in the speaker, then pop the front-facing camera back into its housing. Try to hold each piece down as you go. While fighting this part I was seriously questioning why I didn't spend the extra $49 for the full assembly but eventually things popped into place and I was back in business.

For the four connectors from the screen to the body, just push them in with your fingers. You will feel them click into place.

Good luck!