I always liked "learn by example" methods, so here it goes:
- Download the package from one of the
- Open it with the archive manager.
- You will see some directories. They are structured like you are in the absolute root of the file system.
The runner will have to go in the /usr/bin/ directory. Rename it into "web-pad" or "webpad" and make sure it starts with "#!/usr/bin/python". That way you can easily launch it from command line, without having to write "python web-pad". Instead, "web-pad" will be enough.
The other files will have to go into /usr/share/web-pad/ or /usr/share/webpad/
For the launcher to work, you will need to make a /usr/share/pyshared-data/web-pad or /usr/share/pyshared-data/webpad file. I think it adds your source files to the include path, so the launcher can launch them. Again, as an example of one, use the /usr/share/pyshared-data/software-center file inside the package.
You should also have a look at other files in the software center package. They can provide some very useful information.
And yeah, look at the files in the DEBIAN directory. Especially the control file, as it is where you set the dependencies, description, version, conflicts, etc...
The triggers file allows you to set triggers to your application. (probably launches the application when something is done, but I am not sure. You could always try...)
The prerm script runs before the files are removed. (package removing)
The preinst script runs before the files are copied into their place. (package installing)
The postrm script runs after the files are removed. (package removing)
The postinst script runs after the files are copied into their place. (package installing)
The md5sums file contains md5 checksums of files inside.
The conflies file probably contains the configuration files, although I am not sure about that.
As said by @Flimm, File roller has built-in functionality of opening deb archives in a more friendly manner - this includes unpacking control.tar.gz into DEBIAN directory, data.tar.gz into the root (it contains your files) and hides the debian-binary file. Opening deb files in Ark doesn't do that.
USING FILE ROLLER TO MAKE DEB PACKAGES WILL NOT WORK! FILE ROLLER ONLY SUPPORTS READING DEBS!
You could try this application, I looked at it and it seems quite good: http://debcreator.cmsoft.net/#download