Trouble Unlocking Bootloader on Android Device (RCA Voyager Tablet)
Do you have the USB DEBUGGING CHECKED BOX ON. I know USB DEBUGGER has to be on. Theres also a box about ADB/ADT make sure that is checked along with the setting install from unknown locations has to be on for 3rd party apps other than the ones from google play. It sounds like that is all that has to be on in your settings under Accessibility and under Developer options in your Settings menu.
Your other question about your volume up and down button. You need to shut your phone off then hold down on volume button and power button at same time until you see the Android bootloader settings pop up on screen then let go, somme samsungs you also have to be holding down on the menu key as well as power key, volume down.all at same time till bootoader then hurry let up