netatalk hasn't been packaged with Debian for a few years now. If you don't want to get your hands dirty with compiling the package you can download compiled (binary) deb packages of netatalk version 3 from my GitHub releases. Right now I have packages for netatalk version 3.1.12 and 3.1.11 for for Debian buster, stretch and jessie.
To install the packages:
- Find out the release of Debian you have installed with source /etc/os-release; echo $PRETTY_NAME
 This will output a line of text likeDebian GNU/Linux 9 (stretch). In this examplestretchis the name of the Debian release. Write that down somewhere.
- Find the appropriate packages for your Debian release on the releases page. Out of the several packages for your release you'll need to download the libatalk18andnetatalkpackages. So for my example, I would download the filesstretch_libatalk18_3.1.12-1_amd64.debandstretch_netatalk_3.1.12-1_amd64.deb.
- Download both .deb packages to your local machine through the browser or with wget.
- Install both packages at the same time with dpkg -i. In my example, I would dosudo dpkg -i ./stretch_libatalk18_3.1.12-1_amd64.deb ./stretch_netatalk_3.1.12-1_amd64.deb