Sorry I'm new to this...

I just called Hyatt CS to use my club access awards for a 2 night stay and they told me it's confirmed.
I have 3 questions:

1.
Is the award for 1 night only, meaning you have to use 2 awards for 2 nights, or 3 awards for 3 night, and so on ?
Or can you use 1 award for a 10 night stay for example. ?

2.
I don't use the hyatt app....just the desktop website. Any way I can see if the award been properly added to my existing reservation ?

3.
What happens to the award used if I change the reservation to extend the length of nights or change the rate type AFTER applying the award ?


Thanks in advance