How to add subtitles to a TV-serie DVD (several episodes) keeping menu's?

[snowseals]

Hello,

I want to add Dutch subtitles to an American DVD (=NTSC) with several episodes per DVD.
The DVD doesnt contain any subtitles, so I've downloaded the Dutch subtitles from http://www.ondertitels.com, which are the subtitles from the original Dutch DVD-set (=PAL).

So here's what i've got:
12 episodes splitted over 3 or 4 DVD's, menu's and 12 SRT files.

I want to keep the original menu's, I only want to add the subtitles, so i can tick them on/off by using the remote control of my DVD-player.

Note:
Somehow, based on the Thread https://forum.videohelp.com/threads/277950-How-to-add-new-subtitles-to-an-existing-DVD , Method 1 doesnt work 4 me.
The other method is based on a movie, so u only have 1 continueous subtitle-file to add...
Since the Dutch DVD-set SRT files are based on PAL, and my American DVD-set is NTSC, i have to convert the framerate of the SRT-files, I guess.

Any suggestions what to read, or how-to / tips / etc. would be very welcome!
Btw: I'm using a PC.

[manono]

You can easily adjust the framerate of the SRTs in the 'Synchronize' section of SubtitleCreator. At the same time you can convert them to SUP format subtitles for use in such authoring programs as Muxman or IFOEdit. Other authoring programs will take them in SRT format.

As for adding the subs to the DVD episodes, it depends on how that DVD is authored. If each episode is its own title, it as easy as doing it for a movie, but just more work because it would be like doing it for 12 movies. You'd follow method 2 of Baldrick's guide to which you already linked.