Changing the value/property of a UI control placed in view through controller

Hi,

My development is as follows:

1. index.html

2. App.view.xml

3. App.Controller.js

App.view.xml

I have 3 UI elements in it.

1. Label

2. Input type="text

3. button

What I want to do?

1. On Press of button, I want to get the value in Input and change it to something else and update the value on view to display.

2. On Press of button, I want to change the properties like enabled  of Input element.

I know, this might be very basic. However, I tried looking for it and couldn't find something that might direct me in right direction.
Any help hints or answers will be helpful.

Thanks in advance.

Preetam