Export/Import Bookmarks in Acrobat

Hi,

I have combined two PDF files to create a new, single file. However, the bookmarks only appear for the second file, there is no sign of the bookmarks from the first file.

Can I export the bookmarks from the first file, then import them into the new file?

Or, is there some other way to create a complete set of bookmarks in the new, single file?

Thank you.