Hi. My name is***** you for your question and the opportunity to assist.
Is there a label on the extender that lists the model number?
When an unconfigured extender is powered on it starts broadcasting a wireless network
Do you see that network on your wireless devices?
Once your are connected to that network (it doesn't have a password)
you open a browser and go to www.mywifiext.net or www.mywifiext.com