This isn't urgent, though it would be nice to get it done in the next
few weeks. As with all documentation, the sooner the better IMO...
especially with a product that is updated as frequently as LibreOffice.
The full Impress Guide needs to be compiled from the individual
chapters, using the master document. This may involve a certain amount
of manual fiddling around, as described in "Producing LibO User Guides".
If whoever volunteers for this task is not familiar with the details of
the process, I can provide more info or pointers to info or answer
specific questions.
--Jean