6) To stamp your ID onto the open image select the Brush tool (1) from the tool palette and your ID stamp brush from the drop-down (2) up in the Options bar at the top of your workspace. The new brush will probably be sitting at the bottom of the list as it is the most recently added brush to your current set.

Make sure that the Mode is set to 'Normal', the Opacity set to 100%, Flow to 100% and have the Airbrush set to OFF (3).

Make sure your Foreground Color is set to White (4). An easy way to do this is by pressing the letter 'D' on your keyboard. This will set up the Photoshop default Black for the Foreground color, White for the Background color. Then hit the 'X' key to switch the Foreground and Background colors.