Manually editing debianrules file needed for simple build process?

[Thomas Pryds]

I'm a newbie trying to build a deb to put into a PPA, following this
Ubuntu guide[1], but I run into troubles with the rules file, where I
consult this overview[2] and the Debian Policy Manual[3]. I gather
that in many cases one can leave the rules file as is, in its very
short form, however this does not work for me, probably because a
small amount of trickery is needed before being able to run make on
the upstream package.

The build process for manually building and installing upstream is:

1. cd packagedir/src
2. cp makefile.unix makefile.my
3. Run three sed lines on makefile.my
4. make -f makefile.my
5. sudo cp -f binaryfile /usr/local/bin/

I've managed to adjust the rules file (adding targets) into what
appears to be successfully performing steps 1-4, but when compilation
finishes through the "bzr builddeb -- -us -uc" command, I'm met with
an error that says "dpkg-genchanges: error: cannot read files list
file: No such file or directory", and it makes me wonder if I'm really
doing a lot of work that is not necessary. After all, the build and
install process is not very complicated.

So my question is: Can I revert the rules file, and easily implement
the five steps above in the build process, or do I need to continue
down the road that I've taken, manually editing the rules file? In
both cases I need guidance on how to continue :)

Thomas

[1]: http://packaging.ubuntu.com/html/packaging-new-software.html
[2]: http://packaging.ubuntu.com/html/debian-dir-overview.html#the-rules-file