On the image below this is what I want to do. I want to be able to switch tab options with TAB key.
To save, simply press return
To cancel, hit esc or cmd+.
If you do not want so save, hit cmd+D or cmd+backpace
If you want to use the tab key, you should enable keyboard access by hitting ctrl+F7 Note: Depending on your setup, you might need to additionally press fn to use the function keys.
Once you've enabled keyboard access, you should see an additional blue glow around the currently selected button. You can then cycle with tab (holding shift to go backwards) and select your option by pressing space.