and install it, by clicking "I do not have a product-key" when prompted to enter a key. The resulting copy will not be "activated". So, you can "test" Windows 10, for a few days. Windows Update will run, and may possibly download and install any "missing" device-ddrivers. If it works for you, then you can purchase and use a product-key for Windows 10.
If you have a copy of Windows 8, with a product-key, then disconnect from the Internet before entering the product-key, because Windows 8 will automatically "activate' with your product-key if it finds an Internet connectioni.
Without an Internet connection, you cannot run Windows Update to download/install any "missing" device-drivers.