To watch DVD movies on Windows 10, you need a DVD drive and a DVD player app or program. You can use Windows Media Player if it shows your DVD in the navigation menu. You can also buy Windows DVD Player or another app from Microsoft Store. Microsoft recommends a free DVD player for Windows from the Store. Another free and reliable option is VLC video player, which supports DVDs and Blu-ray. Make sure you download the desktop app and not the Windows Store version of VLC.

Here are the steps to watch a DVD on Windows 10 using Windows Media Player:
1. Insert the DVD into your computer's DVD drive.
2. Open Windows Media Player.
3. Click on "Play" in the navigation menu.
4. Select "DVD" from the drop-down menu.
5. Click on "Play" again.

If you prefer to use VLC video player instead, here are the steps:
1. Download and install VLC video player from their official website.
2. Insert the DVD into your computer's DVD drive.
3. Open VLC video player.
4. Click on "Media" in the navigation menu.
5. Select "Open Disc" from the drop-down menu.
6. Click on "Play" again.