The companion app is available free of charge here: https://zubersoft.com/mobilesheets/compa...hp?lang=en
Please note that the companion app is not a stand-alone version of MobileSheets that you can use to set up your library. It has to connect to a device running MobileSheets and it can then manage the library of that device. If you want to be able to set up the library in an "offline" fashion, then you'd need to install the full Windows 10 version of MobileSheets on your laptop. If you already purchased the Windows 10 version, you do not need to pay a second time to install it on your laptop. Just log in to the Microsoft Store with the account you used to purchase the app and it should let you install your purchase.
Mike
Please note that the companion app is not a stand-alone version of MobileSheets that you can use to set up your library. It has to connect to a device running MobileSheets and it can then manage the library of that device. If you want to be able to set up the library in an "offline" fashion, then you'd need to install the full Windows 10 version of MobileSheets on your laptop. If you already purchased the Windows 10 version, you do not need to pay a second time to install it on your laptop. Just log in to the Microsoft Store with the account you used to purchase the app and it should let you install your purchase.
Mike