changelogshould say "focal" instead of "unstable" (assuming "bionic" is the code name of the Ubuntu version for which you're building the package; adjust the package version number if necessary.
controlshould specify "utils" as the Section; in that file, add the tool's Homepage, description, and specify Build-Depends (which Debian packages are needed to build this one?) and Depends (which packages does it need to run?).
installshould list the source and destination paths of any files that should be copied as part of the installation, one set per line.
copyrightshould include the appropriate copyright and licensing details.
rulesmight need some changes as well, based on what steps need to be taken to build the tool from its source code; the build process can automatically figure this out, so don't tinker with this file unless the build fails.
debuildnot to sign the generated package, since you don't have the REMnux private key. The command will follow the configuration directives in the "debian" subdirectory and (if it succeeds) generate a Debian package file with the .deb extension as well as several files that describe how Launchpad can built such a .deb file on its own.
debuildin the previous step to match the name of your file. If necessary, change "bionic" to match the code name of the Ubuntu version for which you're building the package.
debuildwith Lenny Zeltser by email.