Most of us have experience with devices that are both routers and wireless access points. But those can lead to a lot of dead spots. The UniFi system from Ubquiti splits those duties and gives you a mesh network so you can strategically place access points where you need them, all using a single SSID.
You can read our full review of the UniFi system here. Meanwhile, here is a video that demonstrates how to install a Ubiquiti UniFi network: