Apple TV 4 (ATV4) & .srt files

[Bandr.]

Hi there,

Can anyone tell me how to use/add local .srt files to movies (also local network), when playing it on the tvOS app?
Because the subs download from opensubs does not always work. And also sometimes not available in the preferred language.
If the app can play subtitle files downloaded from opensubs.org, i guess it should play the subs files (with the same location and same name) locally just as well. Right?

Thnx in advance!