If you go to your install directory and open the \\utils folder, there's a program called nwhak.exe. When you open it, choose Resource > Add from the menu bar. This will let you choose which files to put in the hak. When you've added what you want, save the hak (File > Save) in [install directory]\\hak.
Next, you need to add the hak to your module. With your module open in the toolset, choose Edit > Module Properties. From the Module Properties window, click the Custom Content tab. Right above the "Check for Conflicts..." button, there's a drop-down menu. Click it, then select the hak you made. Click the Add button. Click OK.
Remember that anyone who plays your module will need the hak.