Before you open the camera make sure you are electrically ground to earth. The best way to ensure that is to work with ESD-rated equipment such as wristband, mat and special srew-driver. Electrical discharge into the cameras electronics will lead to severe damage!

Remove all screws marked red, the screws with green marks can stay in for now.

After opening the bottom plate you will see the speaker on the position marked with a blue circle. In my case the cable detached trying to remove it, but since I never used the speaker I didn't care. You will need to find another way around it if you want to keep the speaker, shouldn't be to difficult now that you know how the next steps look like.