Manual Sentra 2010

Hol a Atodos request your valuable help to find a workshop manual for the Sentra 2010, specifically I need to know how to disassemble the safety cover where the speakers are housed, to change them but I do not see unicaminte screws some plastic pijas of pressure are seen but I fail to remove it, to avoid damaging it I require your help, to be able to do this task and maintain the current state of the same thanks. I await your answers