Instructions
Download the "Neverwinter Nights" custom module of your choice from the Internet and save it to your computer.
Right-click the downloaded file and select "Extract" to decompress the contents of the archive.
Copy the extracted files to the correct folders inside your "Neverwinter Nights" installation folder. Paste files with the "Mod" extension into the "Modules" subfolder, and files with the "Erf" extension inside the "ERF" folder. For example, if your "Neverwinter Nights" is installed to the default location you would copy the "ERF" files to "C:\Neverwinternights\NWN\Erf."
Double click the "NWToolset.exe" file in the "Neverwinter Nights" folder to start the toolset program.
Click "Create New Module" if you want to add the contents of the ERF file to a new mod you plan on creating or "Open Existing Module" if you already have a custom mod you want to install the ERF to.
Click "File" and then "Import" and select the ERF file you want to use. You will receive a message stating that importing the resources would overwrite resources already in the module. A list of all the resources contained in the ERF will appear. Click "Select All" and "OK" to install the ERF to your custom mod.
Click "File" and then "Save" to save the changes to your custom mod. Exit the toolset and start the game.
Click "New" from the main menu then click "Other Modules." Select the mod that you imported the ERF into from the list and click "Load."