After I download it, the SubnauticaWatcherInstaller is NOT in .exe .

[Adimazurk]

I've even tried forcing it to be a .exe (Open with Notepad, save as .exe) but then it gives me an error:
Version of this file is not compatible with your current Windows(I've got 7)version. And so on...
I find this mod very useful, but I can't get it working :/

[Vlad-00003]

Man, what are you trying to download? You have to get the latest release (btw the project seems dead by now, but still) - https://github.com/MartinSGill/SubnauticaWatcher/releases
Get yourself a copy of subnautica-watcher-release-0.10.3.1217.zip
Then unpack the rar into the subnautica dir (your system should ask if you want to merge the folder Subnautica_Data. You should say Yes).
Then, in the new SubnauticaWatcherInstaller you've just unpacked run SubnauticaWatcherInstaller.exe and you done...