Use the buttons above the Catalog Browser to create, save and close Catalog tabs. Save the newly created Catalog in order to name the tab something else than "Catalog1". The file name will also be the Catalog tab name. The currently visible Catalogs will stay open if you restart IRONCAD, so you don't have to find and open them again next time.
Note: The changes made on the two externally linked parts Cylinder and Crank Case in this tutorial should not be saved. Only the Catalog itself needs to be saved. The Engine file will be closed without saving in the next tutorial.