Encode subs on Avidemux

[Jenny-Sama]

Hi.
I'm an idiot with 0 tech knowledge.

I'm having trouble, for some time now, to encode subtitles using Avidemux, a highly well recommended program for the job.

My issue is, when I open a video on Avidemux, everything is fine and the audio works. When I input the subtitles and click on the preview, the subtitles show up, but the audio is gone.
I've tried, nonetheless, to encode the video like that, and it just ended up a audioless subbed video.

Have pity oh tech gods. Please help.

[Krispy Kritter]

Do you actually need hard coded subs?

To get my video and subtitles into a single file, I simply drop a video file and sub file into MKVToolNix and the output is a mkv file.

I've not used Avidemux (which appears to be a conversion tool...thus you are changing the file type and likely the quality), but there are several guides on the bottom of the tool page here: https://www.videohelp.com/software/AviDemux