To download video, visit the video info page, and then select the drop down menu.
From here select Download Video.
This will provide you with the original source file.
If you uploaded the video as an MP4 you will be provided an MP4.
If you recorded the video using the platform, a separate tab may open with a webm url.
Smaller files tend to download directly.
Larger files will open in a separate tab.
If the video opens in a separate tab, Click the 3 dots in the top right corner and select More Tools, then Save Page As...
Here is a tutorial gif.