Prior to creating a new parts list, use the Set Pressure Network Catalog dialog box to select the catalog that will serve as the source for components used in the parts list. A pressure network parts list can contain parts from only one catalog. Each pressure network catalog is comprised of a single SQLite database.
The default pressure network catalogs contain a wide variety of pressure network parts. Parts in a catalog can include pipes, fittings (such as bends and tees), and appurtenances (such as valves).
- Click Home tab
Create Design panel 
Set Pressure Network Catalog Find. - In the Set Pressure Network Catalog dialog box, specify the Catalog Folder and Catalog Database File and click OK.
- Set up a pressure network parts list.
Note: A Catalog Editor is available for editing the metadata on the parts. The program is Autodesk.Aec.Content.CatalogEditor.exe and can be found in C:\Program Files\AutoCAD 2018\C3D. This program allows you to edit the metadata on pressure network parts, but not create them.