1) Some tips before we start
See the red line on the picture below, that's the screen seam. The screen seam separates the screen from the rest of the phone (This is the place that you should pry up when opening the front).
2) Heat the screen
Use a heat gun or a hair dryer to heat the right edge of the screen for around 30sec to soften the adhesive.
3) Insert opening pick
If your screen is badly cracked make sure to cover the whole screen with a layer of clear packing tape. Now apply the suction cup as close to the right edge of the screen as possible. Pull onto it in order to create a gap and insert the pick into that gap.
4) Insert the pick without damaging the OLED panel
Get the pick upwards to a steep angle as shown in the picture below. Then slide it below the OLED panel for about 6mm. If you feel the point hitting the ridge stop immediately.
5) Cut adhesive all around the phone
Slide the pick all around the phone in order to remove the adhesive and separate screen from the rest of the phone.
6) Open the screen
Lift the screen from the top edge and swing the screen over the bottom edge like shown on the picture below.
7) Uncover the display connector
Use your fingers or a pair of tweezers to peel the black tape that is covering the screen connector bracket.
8) Remove screen connector bracket
Use your T3 Torx screw driver to remove the two red circled screws that are securing the screen connector bracket. Then simply remove it.
9) Disconnect the screen connector
Use a tip of flat spudger to pry up and disconnect the screen connector from its socket.
10) Remove the screen
Simply remove the screen. Scrape off all remaining adhesive from the frame.
11) Reassemble everything with the new screen
Your Pixel 4a is completely disassembled. Now take your new screen and reassemble your phone by following this guide in reverse order, and then test everything up to make sure you did everything properly.
Test everything up
Congratulations, you changed your Pixel 4a screen all by yourself. Now just test a few things to make sure everything is working properly:
-Test the brightness of the display.
-Test the touchscreen, select an app, and drag it all around the display. If it is following your finger everything is fine.