Basic recap; you need to install
JSGME (generic mod enabler) to you game's root folder (..\Ubisoft\Silent Hunter 5\). Run the program once, and it will prompt you to create a new folder where you can place your mods. It's called "MODS" by default. Close the program and check if the folder was properly created (should be inside the "Silent Hunter 5" folder).
Move/copy your mods in that folder, and they should show up in JSGME's left pane. Select one and click enable (arrow pointing right iirc).
Make sure the mod is in good order though; should have a folder with the mod name, and in that one called "data" and possibly another called "Documentation".
If you don't have the "data" folder directly blow the mod's folder, the files will end up in the wrong place.
