Whoa. If you can come to terms with the idea that Captivate
doesn't deal with "layers" you will be a happier user (it is not a
graphics application, exactly, and you appear to be treating it as
one, or at least expecting it to act like one).
So to start over, you have imported one or more PPT slides
into Captivate as a new movie, and now you would like to change the
background for slide #1 (or whichever). There are ways to do what
you want:
Way #1: Right-click slide #1 and select "Copy Background".
This will place the background image on Windows clipboard, so you
can then open your favorite image editor, paste the clipboard as a
new image, make your edits, then copy the changed image back to the
clipboard and reverse the process . . .
Way #2: If the background you would like to change to is on
one of the slides in this movie, you can copy the background from
that other slide, then paste in to slide #1. Same idea as "Way #1",
but all done internally within the current movie.
Way #3: Select any image and resize it in your favorite
image editor to be the same size as your existing project, then
insert it via the CP "Insert > Image" menu, position it, then
right-click and "Merge" it into the background (replacing the
current background with the new image).
Where you set the background color for the entire project is
at:
Movie > Preferences > Preferences (tab) > Movie
Background Color
Last thoughts: Think of your Captivate movies as a background
(it can be a captured image, or a "Blank", etc.) on which you (or
Captivate) place various other objects including other images,
highlight boxes, text-caption boxes, and so on ... as well as
interactive objects such as click-boxes and buttons. Everything can
be altered in one way or another.
Specifically regarding "layers": We don't normally refer to
"layers" but ifit makes you feel good, go ahead. The objects on the
bottom of the timeline "stack" are the bottom layers, and the
higher on the stack they sit, the higher the "layer" they occupy
(like I said, we don't normally talk this way, but anything to
accommodate ...).
You can easily change the "layer" of any object EXCEPT (1)
the slide itself**, which always occupies the bottom layer UNLESS
there is audio on slide-level, in which case ... (2) any audio
placed at slide-level is locked as the bottom layer, with the slide
itself sitting on top of it.
**The slide itself
contains]\ the background image (if any exists for that
slide) - as an integrated part of that slide.
From the type of question(s) you are asking, it might be very
helpful to watch the half-dozen Captivate tutorial movies that are
a part of the install package. They are all listed in the
right-column of the main user interface. Best of luck!
.