Indeed, the entry appears empty, but that could happen because no info was added, yet. However, for Realtek, you will have to know exactly the model in order to install the driver. If it's a PCI card, look on the big squared CHIP. It should say the model number, then you can use the downloads from the official website to save the package.
Secondly, if the network adapter is embedded into your motherboard, then visit the official website of the motherboard to download the necessary drivers.