Hello: I am a Samsung Galaxy Grand prime plus user, and I have a dual disability. I operate the Android operating system on your device. I use Android 6.1 Marshmellow. I am blind-visually impaired, and I use the screen reader talkback to access information on the screen. Added to this, I have hearing in only one ear. The problem i have is that I cannot use the earphone in both ears. I have to listen to it in one ear, that is my left ear. I have at different times attempted to change the sound from stereo to mono, but this has always been impossible. That option is disabled. Again, the sound is balanced in both ears, at 50 percent. One is aske dto change that by moving the slider with one's finger. I don't know how and where to find the slider. The question now is: how do I enable to option to change from stereo to mono, and how do i find the slider. Galaxy Grand prime to the USB Finally, is there a specific opener for the sim tray so that I can insert my Micro SB card. The model number of my phone is: - SM-G532FZDDXFA Hope to read your response.