You can download prebuilt package from 'releases' section of this repository. Please report back with problems.
Install required packages:
apt install git devscripts dh-systemd unzip build-essential
Build debs:
git clone https://github.com/Gregy/znapzend-debian.git
cd znapzend-debian
git clone -b v0.19.0 https://github.com/oetiker/znapzend
cp -r debian/ znapzend
cd znapzend
debuild -us -uc
Resulting packages are in parent directory