It's very easy to navigate into and within the extension by using the keyboard only.
All you have to do is,
Press the "Tab" button once your browser triggers any type of a pop-up. You will see the below highlighted button pops up on your screen.
2. Press the "Enter" key to activate the funtion.
3. Press the "Tab" button again. This should highlight the close button of the pop-up.
4. Press the "Tab" button again in order to move the highlight to the buttons below.