Questions about submitting a package

[Jesse Smith]

I have been reading the documentation on publishing a package/app and I
have a few questions about Step 5, packaging the app. Specifically I'm
curious about:

1. "Be in one, self-contained directory." Does this mean my application
plus any dependencies have to all be packaged together? My app relies on
the SDL library, which is included in Ubuntu's repository. Do I have to
include SDL in the package I submit?

2. "Be able to be installed into /opt/pkgName". By what method? Do I
need to supply a binary package which will install to this location, or
are we talking about a source-level flag like "make install-pot"? Can
the package also install to other locations or must it always be
installed to /opt/pkgName?

3. Does a non-commercial app I submit have to be in binary or source
format?

4. The video tutorial shows software being published through LaunchPad.
Since the software already has its own website, do I need to also
publish on LaunchPad?

The only tutorials I can find on the site assume the developer is using
Python and Quickly. A step-by-step guide to packaging a C/C++ program
would be really helpful.

Thanks in advance,
Jesse