Luwra is a header-only library, which means that nothing has to be compiled in order to use it. Simply clone the repository or download and extract it to a directory of your preference.
For your application to be able to reach the lib/luwra.hpp header file, you must add
/path/to/luwra/lib to the list of include paths. With Clang and GCC that is done using the
-I/path/to/luwra/lib command-line parameter.
Now you can simply #include <luwra.hpp> in your C++ files and start using Luwra.
A reference manual exists here.