You create a new IBuildCatalog object by calling the IBuildCatalogs.Add method, as in the following example, where KMSampleCatalog1 is the name of the catalog:
Option Explicit
On Error Resume Next
Dim objSearchAdmin, objBuildServer, objCatalogs, objCatalog
Set objSearchAdmin = CreateObject("Search.SearchAdmin.1")
Set objBuildServer = objSearchAdmin.BuildServer
Set objCatalogs = objSearchServer.BuildCatalogs
Set objCatalog = objCatalogs.Add("KMSampleCatalog1", _
"C:\Catalogs)
...
'Release objects
Set objCatalog = Nothing
Set objCatalogs = Nothing
Set objBuildServer = Nothing
Set objSearchAdmin = Nothing