Actually, it was simple, if scary. Never even opened a phone before, but it was a "no warranty," unlocked phone, so I checked the "How tos" on you tube, and ordered an "LSHtech LCD Display Touch Screen Digitizer Assembly for LG G4 with Frame" from Amazon for $58. The "with frame" is the key - it obviates much delicate labor for $10 more, so a no brainer for me. The YouTubes didn't make it clear that there is a tiny rubber piece where the phone's proximity sensor is that must be transferred to the new frame, so i thought I had ruined the phone because, while it would boot, there were many problems without it, including not being able to make or receive calls. Screen itself is excellent, good resolution, color and brightness.
Opened it again and made the swap, and it seems to work perfectly except for the ear piece speaker. Phone jack and speakerphone ok. Some have replaced the part, but it still didn't work, so thought I would check in for ideas here.
JohnW