You can delete your previously added YouTube videos individually and you can also delete the entire folder with all the videos that you added by following the below instructions:
Step 1: Click on videos.
Step 2: Click on the name of the folder where the video you wish to delete is located.
Step 3: Click on the delete tab next to the video.
Step 4: Click on save changes to confirm you wish to delete the video.
Note: You cannot delete a folder with videos in it. You will need to delete each video one by one in order to delete the folder. This step is in place to ensure a folder is not accidentally deleted that contains content.