Speaker grille. Carefully pry out with very sharp knife.

Volume buttons. Carefully pry out from the middle with a very sharp knife. The rigid white plastic holds in the ends, while soft green plastic also clip in the middle area.

Call/hang up button. Here the soft plastic is clear, but extraction is same as for volume buttons.

Note that the inserts are not symmetrical. Keep track of how they came out here, and re-insert them carefully to ensure you get them the right way round.

Be sure to do this step! The inserts will prevent the removal of the innards.