After removing the back casing, then rotating the screen back to the screen up facing. Your going to carefully put the LED screen back into the panel. The screen fit's snuggly into the groves like the 1st image. start from the bottom up, ensure the botton circuit strips are not trapped under the LCD panel.

Having done teh above, it's really easy to get those strips under teh LCD pannel. It's also hard to remove them because of the way the pannel is designed. So starting at the bottom first is the best way to ensure theser not trapped.

Once it's been aligned so it feels almost flush, do a last bit of alignment and ensure the connector strips at the bottom are not tangled up. Some people tape the conncetor to the screen to avoid this.

Carefully tip up from the bottom the screen with the LCD panel in the groves. Then slip the connectors under the clips to hold them in place safely for the next step. Before lowering the screen down.

Now carefully after checking the LCD pannel is still in the groves and has not slipped out. Get the outer frame and carefully slip and click it back into place. locking the LCD pannel safely and securely.

Flip the screen arround, to the cirecuit boards on the back.