If you properly specified the SAMSON_SDK_PATH, and you still cannot see files in the project that might be due to CMake Generator settings of the chosen Kit in QtCreator during the "Configure Project" step.
To check with different CMake Generator settings got to Projects -> Manage Kits and choose the Kit you are using. You may try to modify the CMake generator settings, e.g. to the ones shown below, but be aware that they depend on what packages you have installed.
You can read more on setting Kits in QtCreator here: http://doc.qt.io/qtcreator/creator-project-cmake.html