That may work for inserting only one slide, but what Anne wants is to
insert an entire Impress presentation, not just a slide or two. This can
be done with LO 5.1.6.3 (which is what I use), but it apparently is
missing in later versions. I can understand and appreciate Anne's
frustration that a former functionality seems to have been deliberately
removed from the program (unless it has just been moved to another
location on the menu, which nobody seems to have been able to find).
Yes, a person can copy and paste select slides, but that is hardly a
satisfactory answer when she used to be able to insert an entire file
and can no longer do so.
Virgil