Download video using button

I am trying to have a button on my website that when clicked, downloads a video file. The file is already stored on my website.
However, whatever I do with web properties, clicking the button simply plays the video in a new window.
I can right click the button & download the video, but that's not what I'm looking for. The button is labelled "download", and that's what I'd like it to do.

This must be easy, but I can't find any info on how to do it?

OK. I found a convoluted way around the problem:
For each button group, I edited the text on the button to what I wanted, then saved the button group as a bitmap.
Then add a placeholder with html along the following lines:
<a href="C:\Users\keefy_j\myvideo.mp4" download> <img src="C:\Users\keefy_j\DownloadButton1.png" ></img> </a>

There probably is an easier way, but this works, so I'm good.