@anchored 

The easiest way to set up the RE220 is probably using our Tether app. Before you begin first make sure you have the correct wireless password of your Wi-Fi or the extender will never connect. Factory default the extender by holding the reset pinhole for 10 seconds while it is plugged in.

With your smartphone go to the Wi-Fi settings and forget the wireless network that you normally connect to. Connect back to your Wi-Fi network so it prompts you for the wireless password, enter it until you connect back. This is the password you will give the extender when connecting it to your wireless network. There is another password you set up on the extender, but that is only to log into the extender which you do when first configuring the extender.

Here is the FAQ that walks you through setting up the device. I would first recommend having the extender in the same room of the router, and then move it to where you want to after (configurations are saved): https://www.tp-link.com/us/support/faq/1373/

@Tony 

Thank you Tony.