For be able to run this examples you must have in your computer Qt-5. To install follow the installation guide from the official docs.
To install each example on this repository, you must go into the example folder run qmake than run make, than to run the example you can just use ./example_name. See the example bellow.
$ cd ./draw/
$ qmake
$ make
$ ./draw
If you want to, you can use Qt-Creator and just open this project and build it using the Qt-Creator.