How to convert a DVD to include subtitles?

[ikofig]

I want to convert a DVD and have the full (meaning not just the forced ones) subtitles displayed in the converted file (only one set - English, which is the only subtitle available). The default Subtitle track setting is "-1" (I have no idea what that means) and with this setting the DVD converts with no subtitles even when I have the subtitles on for playback. Changing the Subtitle track setting to 0 or 1 had no effect - the subtitle does not appear during playback of the mp4 file and is not available to be displayed.
How is it supposed to work?
Thanks!

[ikofig]

Isn't there ANYONE out there who knows what the "-1" in Media>Convert/Save>Open Media>Disc>Audio and Subtitles>Subtitle track means?
How should it be set in order to embed a subtitle in the converted mp4 file?

[Lotesdelere]

https://wiki.videolan.org/Rip_a_DVD/

On a side not it might be easier to do with programs like Handbrake.
https://handbrake.fr