I fixed my son's iPhone 5C broken screen following the iFixit video and instructions – which are excellent! I needed to organise things carefully, follow the instructions in the video and take my time. I put it all back together and it worked first time :-)
Tip: the screws are tiny and easy to lose, so I suggest using a container with raised edges to contain them. I used strips of PostIt notes to labels the different parts.
Thank you iFixit – your instructions are by far the best that I found online!