How do I find the best location for placing the EX6120?

Place the extender in the same room as your router initially for setup. Once configured, move it closer to the area with poor WiFi signal while staying within range of your existing router. Use the Router Link LED and Device Link LED to optimize placement: if Router Link LED is amber or red, move closer to the router; if Device Link LED is amber or red, move closer to your devices. A clear line of sight with no physical obstacles between the extender and router provides the best connection.