Hopeless

I finished making my music video and stupidly pressed the red and blue 'Start' and 'End' tabs (don't even know how) and now, every time I try to export my completed video, I am being told that because those tabs were pressed, only the video between the two will be exported - just 11 seconds. The trouble is I cannot find how to 'undo' or rectify this. Can anybody help?

I am in my seventies and all this 'techy' stuff is like trying to learn to fly a Klingon spaceship to me, but I persevered using the free trial of Videopad and with infinite hours of googling and trial and error, and I am slowly getting there - the key word being 'slowly'. I was emboldened enough to buy the full version of Videopad, but I now have a problem; In the trial version, I had a separate 'Audio' track which I found easy to use, but on this version, I can't find a separate audio track just a 'linked audio' and when I follow instructions and drop the music track onto the sequence the title and image of the audio track jumps onto the start of the video sequence which I made, and the soundtrack stays directly underneath it. I am trying to create a video and soundtrack which play together - all image clips placed in order to match the words of the song as it plays. I hope you understand me. I have tried using the Videopad tutorials, but they all seem outdated or seem to be using a different version to me - one with a separate audio track, like I had on my free trial version. I would appreciate any help from anyone. Thanks