How to add subtitle (.srt) file to Quick Time Player while playing a video ?

I tried to add a subtitle file (.srt) file to QT Player while playing a video. But it is not showing the subtitle file and also I'm not able to add it.

I have my video with respective subtitle (.srt) file in the same folder. But it's not detecting the subtitle file present.

Note: I also tried with .qt.txt subtitle file. It's still not detecting.

Is anything am I doing wrong ?