Installing the plugin

In Stash, go to Settings → Plugins → Available Plugins → Add Source and add whichever URL matches the machine Stash itself runs on (not necessarily the one running the moansubs server):

Stash's architecture	Source URL
linux/amd64	https://plugins.moansubs.org/plugin/amd64/index.yml
linux/arm64	https://plugins.moansubs.org/plugin/arm64/index.yml

Install moansubs from that source, then Settings → Plugins → Reload plugins.

Settings

Open Settings → Plugins → moansubs:

• moansubs server URL — leave this empty to use the public node at https://moansubs.org. Only fill it in if you're pointed at a different server.
• Upload token — your account's token, from the website's /me page after you register. Only needed if you want to push subtitles or vote; searching and downloading work with nothing set here at all.

If your Stash instance requires you to log in, it's also worth setting Stash API key (from your own Stash account) — the plugin otherwise relies on your browser session, which can expire partway through a long bulk task.

Turn on perceptual hashing

This is the step that actually matters: Settings → Tasks → Generate → "Perceptual hashes". Across two different people's libraries, files are almost never byte-identical, so oshash alone rarely matches anything. phash is what actually finds subtitles for a re-encode or a different rip of the same scene.

Once that's done, open any scene page and look for the Subtitles section — see Finding and downloading subtitles.