The perfect tool for this job is Auto Movie Creator. Auto Movie Creator has built-in scene detection, which will automatically detect the changes between different videos and help you split them into separate clips. You can export your movies in YouTube's recommended format for uploading, which is MPEG 4 at a screen size of 1280x720 pixels. You can read more about Auto Movie Creator and download a free trial version here: https://www.deskshare.com/amc.aspx