I made my first video yesterday. It’s about public speaking and speech writing. I’m very pleased with the video. Unfortunately, I uploaded my B-roll without seeing the instructions. Consequently, it shows many mistakes: it's 12 seconds long instead of about 30. It does not open with the image of my book cover, does not show the back cover, or the spine. (It's only 12 seconds long because I did not initially know how to upload a 30-second video.) My question is: going forward, will I be able to use my 30-second B-roll instead of the 12-second one? Also, I chose a presenter on a panel for my video. Should I keep this presenter for my next four videos, or should I choose the podcaster or something else sometimes?