In a case where you may not have any wired infrastructure, you have the following Choices:
1. You can install Ethernet cables in your walls using outlets.
2. You can do the same as thin as number one, only with a cable management access floor instead. Check this: https://www.netfloorusa.com/comparison-cable-management-methods
3. Buy and hook up modems like the TP-Link AV200, which carries Ethernet through the electrical connections in your home.
4. If you currently have Wi-Fi installed, then use a Wi-Fi to Ethernet converter. There are several to choose from, but I prefer the NetGear WNCE2001.
Best of Luck to you!