Navigate to the video on Youtube that you would like to add to your listing. Choose the share option, then the embed option. Copy only the video url.
Navigate to the video on Vimeo that you would like to add to your listing. Choose the share option and copy only the video url from the embed code.
*Note: If you are having trouble selecting only the url you may need to copy the entire embed code, paste it somewhere else like a word document editor, and than copy the url.