You can easily set up your rockspace extender by pushing the WPS button or you can also do the setup with http://re.rockspace.local URL.

Follow the steps below for Rock Space wifi Extender Setup:
First of all, plug your re.rockspace.local into the power outlet and wait for the light to be solid.
Use your devices such as a computer or mobile phone and connect them to the extender's wifi (TP-Link Extender_EXT).
Open a web browser and type re.rockspace.local login in the address bar.
It will take you to the login screen, here you can create your login password for the future login and click on NEXT.
After clicking on NEXT, select your wifi that you would like to extend and enter the password for it.
Finally, after typing the password, click on Extend.
It will take few seconds to apply the settings and after that, you suppose to get 2 solid lights on it (Power and Signal).