How do I a create a vessel’s NMEA 2000 network file (boat file)?

You create, or save, a boat file through the file menu within N2KAnalyzer. First, left click on the "File" menu item found near the top left hand side of the N2KAnalyzer window. Next, left click on the "Save As..." menu item.  A file browser window will appear with the default location where N2K boat files are normally stored. You can use the default directory or change the directory if you desire. Make sure you fill in the name of the file you want to save, and click the save button to write the file to disk.