Can somebody help me? My tax filing was stuck to preparing mode and i couldn't cancel. I bought the program at costco. what should i do?

Do you mean you started in TurboTax Online, but now you want to use the desktop software?   If so, that is no problem.  Install the software and when you are ready to start using the desktop software, you can either start fresh or sign in to your TurboTax Online account from the desktop software to transfer the work you did online to your desktop tax return.    If you mean something else, please reply and clarify.