First take backup of your old apt-configuration files, at least those
you are about to replace with mine.

Put all these files to directory: /etc/apt/

apt.conf
sources.list

You definitely need to edit apt.conf and sources.list. Lines starting
"#" in sources.list are comments. In all other files lines starting "//"
are comments. You may want to copy-paste some stuff from your old
configs to these new config files. You took backups, didn't you?


On the other hand, you can just edit your original configs and take
influences from my configs.