How do I use plugins with this version of mpv?

[mwnDK1402]

The manual doesn't apply to this distribution of mpv, so I would like some help in figuring out how to get plugins to work.

input.conf seems to work when I place it in %LOCALAPPDATA%\Packages\519Ezhik.mpvUnofficial_xfkyq1j2kc7zp\LocalCache\Roaming\mpv.
But installing Blackbox (as an example) in this directory doesn't seem to work.`

I can't exactly copy the error from the application, but it's something like:
Error: Cannot find module file 'Options.js

The paths it spits out also seem to be completely wrong, since it's looking in %APPDATA%/mpv, which doesn't exist. And installing Blackbox there doesn't help either.

A guide on how to install plugins would be much appreciated, given that the paths are different from a normal installation of mpv.