Trouble linking extender without waps

Hi all.
I am trying to set up the wifi extender without waps.
I have seen videos which show me easy set up with a router pushing the waps on the router and waps on the extender but I don't have access to the router only the password to the wifi.
Wifi signal is stronger in one room but not in others so I brought a netgear N300 wifi range extender model ex2700.
According to YouTube videos I should be able to turn on the extender- click on wifi options on my device(for me, phone) connect to netgear_ext and the in my browser go to mywifiext.net , log in and follow instructions. However when I click the wifi options and connect to the netgear_ext , it tells me - connected but 'no internet connection '. I have the netgear app and trying to login.... admin and password but it says loading but never loads.
Can anyone advise, what I'm doing wrong, if It only works with a laptop, not a phone, if the only way is with waps?
Or if I've just missed something silly. Thanks in advance.