How do I know what's broken?

I dropped my phone, and it finally gave up. The glass is cracked, but it still responds to touch, so I'm assuming the digitizer is okay. I remembered the button placement and mirrored the screen to my Chromecast, so yeah it seems to still be fully responsive when I tried it out (I think). BUT, the display is flickering between light yellow and green and then a very green normal display with all the icons. Majority of the time it's a solid color though (with no visible image. What parts would I purchase? I can probably figure out what tools, BUT I'm not sure if only the glass is the problem. So do I need to buy more parts than just the front glass if the display is messing up?