i am starting to learn platformio and i started by creating a new project. I want to simply create a led blinker for arduino. I created the project but the main file and the frameworks are missing. Is there a way to create a basic project with the frameworks?
You can always add your files in the src folder as e.g. src\main.cpp.
Note that framework files (Arduino in your case) are not kept in the project, but are installed as global packages in C:\Users\<user>\.platformio\packages\, and then e.g. framework-arduinoavr. The framework (and compiler, tools etc) will be downloaded on-demand when they are needed, so you might want to just Build the project to make PIO download the framework files etc.