Hi, I'm Ashik. Welcome to JustAnswer. I'm reviewing your question now, and will post back with your reply ASAP
After dragging the files to the CD or DVD, you have to burn it to disk. So the once files are transferred to disc, click on File menu and select Burn disc. Follow the onscreen instructions to burn it to disc.
Refer this article --> https://support.apple.com/kb/PH19009?locale=en_US
The article is for Yosemite, but it is the same procedure for El Capitan. Remember, this procedure will write the videos to disc as a Data format and it may not play on DVD Players. But it will play on all computers.
Let me know how it goes