Built on Ubuntu 18.04 and 20.04 (AMD-64 processor). Mileage may vary with other versions of Linux.
You have the choice of a single pre-built package file, or of installing and building from sources. The single package file is strongly recommended, only try to install from sources as a last resort.
Download the appropriate file for your system
Ubuntu 18 kaffelogic-studio_4.1.2_amd64.deb
Ubuntu 20 kaffelogic-studio_4.1.2_amd64_ubuntu20.deb
Fedora etc kaffelogic-studio-4.1.2-1.x86_64.rpm
and double click to install.
If you can successfully install and use one of the pre-built .deb or .rpm files, then you should do so.
If you need to install from sources, then be aware that this is not a standard Linux install. There is no configure and no makefile. Follow the instructions in the file ubuntu-readme.txt.
Kaffelogic Studio 4.1.2.tar.gz.