I followed the simple one-sentence instruction here to create a simple CLion project from scratch. It works and I can debug it. Now I wanna replace it with my existing C++ sources, that is, adding tens of existing C++ source files into the scratch project and replacing the main.cpp with my own. But after copying my source files into the project directory and search the GUI of CLion and google, I just can't figure out how to do that. So, are CLion users supposed to edit CMakeLists.txt file manually to accomplish this very basic work? How can I add existing source files into the simple scratch project in CLion using only mouse clicks and menus which is a common operation in NetBeans and Eclipse?