calibre broken in synaptics

[leszek]

sorry i'm not that linux-literate...what am I doing wrong?

You need the deb-src lines in /etc/apt/sources.list.d/netrunner.list and debian.list activated or add a deb-src line (identical to the deb line but instead of deb at the beginning deb-src)

do I need to create a "calibre folder" and name it "calibre folder" and put it somewhere? where?

apt-get source calibre will download the current version from the repository and create a folder which you need to cd into.
apt-get source only works if the deb-src lines are active (see above) and you run sudo apt-get update before so it knows where to get the sources from.