EX6100 wifi extender set up troubles

Hi I've been trying to install the range extender without much success.  the genie didn't start up, so connected directly and went in through 192.168.1.1. Had trouble with passwords, but thought I worked it out, There was no check box allowing me to use the same security settings.Can I have a different password on the extender from the router?  Still couldn't access any wireless devices properly. had all green lights, but no internet and each item required a login and password - would it be admin/password?  What happens if I don't connect them all before clicking continue (page 11 of set up guide)  Can they be connected later?

This morning tried again, still no internet access, and couldn't get an windows device to connect to the network at all through the extender.  Went through the factory reset then updated firmware bypassing genie.  Now it wants me to sign in but won't accept admin/password.  What do I do now?

(I'm tempted to throw it away, but a waste of money).  All I wanted was something to plug in which would make the existing wireless network stronger at the other end of the house.