ah ok, I read that, but the numbers vs item numbers was the confusionAccording to the online Help document, it's a 3 step process:
First, open the assembly, reorder the tree as desired, and Generate Numbers to give each component a number.
Then Analyze + Bill of Material and click the Define Format button on the bottom. Move the Number property from the Hidden list to the Displayed List.
Finally, use the Save As button to convert the Bill of Material to Excel format.
Here's the Help document with all the instructions: http://catiadoc.free.fr/online/cfyugpst_C2/cfyugpst0100.htm