Instructions
Download a mod for "Silent Hunter 4." Mods are available for free from a variety of file hosting and fan sites, such as FilePlanet, FileFront and Subsowespac.org. Once downloaded, the files are in a compressed format.
Extract the files from the compress folder with the file extraction program of your choice, such as WinRAR, WinZip or ExtractNow. To extract the files, right-click the compressed folder, click "Extract..." then choose any directory.
Place the extracted mod files into their appropriate folders of the "Silent Hunter 4" directory. Depending on the type of mod you download, it could be placed in a variety of places. However, the instructions for where to install a mod file are almost always either listed in a "Read Me" file that comes with the mod or in the file's description from the site you downloaded it from. Most of the time, installing mod files, such as different submarine skins, is as simple as replacing the existing files in your "Silent Hunter 4" directory with the modded files of the same name.