First did instructions in --> INIT.TXT
Then make sure you have an "empty" repo.
reprepro -b /repo remove bionic whatever # if needed
Until it's empty, then, if you didn't already at some point:
ssh-keygen -f keys/ssh < <(echo "\n\n")
Then:
sudo tar -czf secret.tar.gz keys gnupg repo
# might print some errors on special files, can be ignored.
Upload that thing to some secret URL you can use during CI.
---
Usage after all this:
# install key
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 5CE16B7B
# install repo
sudo add-apt-repository "deb https://cppse.nl/repo/ $(lsb_release -cs) main"
# enjoy
sudo apt-get install whatever