The newly purchased screen will likely not have speaker grills so you must remove them from the broken screen and put them onto the new screen

On both the upper and lower speakers remove the speaker foam that is adhered lightly. Peel away gently. This foam will not be reused so its ok if it gets torn.

Locate the two tabs that holds the speaker grill in place. Highlighted in photo with yellow arrows.

Push out the speaker grill by forcing either one of those two tabs out of the frame by pushing onto the tab with a tweezer end. It requires a bit of force and it will pop out.

The photo only show the lower speaker grill removal, but the upper speaker grill is removed in the same manner.