Can I extend my WiFi signal into my garage with an Apple AirPort Extreme

[LenC]

I'm not too network savvy.
We have Telus fibre service.  Nokia ONT, T3200 gateway. When I go to the garage/shop and listen to Spotify with my iPhone the signal gets dropped intermittently.  I have to walk back into the house with my phone to pick up the signal again.
I have an old Apple Airport Etreme, and 100' of Ethernet CAT 6 cable.  I plugged the cable into one of the LAN ports on the router, ran the cable out to the garage and tried it in both the WAN and LAN ports on the AirPort, but it did not seem to make any improvement.to the WiFi signal.
Any suggestions / education would be greatly appreciated.

[Nighthawk]

The ethernet cable would have to be in the WAN port on the Airport. The Airport will also have a separate wireless network from the T3200's so you have to make sure your phone is connected to it.

[LenC]

Uh, I get it. That separate network or WiFi. Thank you. I will give it a try tonight and let you know the results
Sent from my iPhone

[LenC]

Awesome Nighthawk, thank you.
I had another thought.  Could I plug the ethernet cable directly into the Nokia 7368 ONT? 
I recall reading posts that said this could screw up the Telus network, or Optic TV signal.  
What do you think?