Sorry, @devon assumed you were linking to YouTube videos on line.
By the way welcome to talk.tiddlywiki, even silly questions are allowed, but I am sure we can find you a perfect solution.
If you can get a free account to host your videos online then embed that video, visitors to your site will not use too much of your websites bandwidth.
If the video is local to your device, a file, and only for you another approach is using the external content. There are plenty of existing discussions about this for example How to embed video like [img[xxx]]
- If Its one small video just import it and transclude that tiddler where you want it, should work (untested by me today)