Help Upload video to different Youtube channel



I would like to know if there is a way to upload a video from my gallery to a different Youtube channel (that I set up for family videos) right now all uploads go to my business youtube channel. Note, both are gmail accounts. Also, I have gone into >Google, Settings, Google Account and changed it to the family video channel but the upload still goes to my business channel.

In the manual it says "Tap the Google Account that you want to use" but I don't know how to do this.

Also, is there a way to take a video that I mistakenly uploaded to a youtube channel and transfer it to another youtube channel.

Finally, and on another subject, is there a way to stop the screen from going blank (black) when I am checking my voice messages and I put the phone next to my ear. I would like to keep the screen on so I can easily navigate the keypad.