How can I tell if my extender is working?

to tell if its working? look at the leds. The manual walks through what each means and one's a "router link" light. another shows wifi and client connections.  

Or tell us more info like

1. what extender are you using? 

2. What firmware is on it? 

3. What router is it connected to? 

4. Are you streaming over 2.4ghz or 5gh? 

5. What device are you using for streaming.

6. how far from the router is the tv? 

7. how big is the home and what materials is it made from.