You can download pre-compiled version from releases. To use the engine, unpack the file somewhere in the filesystem and specify the path to zeppelin executable in Your GUI program. Since v0.1.0 version, the program contains only an executable, without any additional binary files, thus specifying a working directory is no longer necessary.
If You want to build the program from source, You'll need cmake and gcc (or mingw on Windows). Using ccmake or cmake-gui is the easiest way to specify all the parameters, that cmake needs to build the engine. Cross compiling is possible, but only one way - from Linux to Windows.
git clone https://github.com/jszczerbinsky/zeppelin/
cd zeppelin
# You may use cmake-gui . instead of ccmake
ccmake .
cmake --build .The executable should appear in build/ directory.
If You want to rebuild the program with overriden files in res/ directory, You should delete all .o files in project root. Otherwise the previous ones will be linked.