Hi
Download Subtitle Workshop from
https://www.urusoft.net/home.php?lang=1, which is shareware…
and read their manual. Encore supports .txt files.
I suggest you look at an .srt file from any commercially marketed .avi movie (which can be automatically converted by Subtitle Workshop), save it and look at the .txt output. Format your own subtitle track in the same way, save it and import to Encore (Timeline> Importsubtitles> Text Script) If you got the timecode right your job is done. If you didn’t you can alter the synch of all or any of the subtitles in SW.
I’m sure you resolved this ages ago, but it seems to be a common problem
Richard