To work this display, enter three numbers in the x, y and z slots on the display for the first vector. You will have to hit enter for each of the x, y and z components. Watch the vector displayed in the space cell for changes as you enter each component. When you have the numbers you want, click on the Action button to lock in that vector. Then enter another three numbers for the second vector. When you are happy with that vector, click on Action again. This will automatically display the angle between the vectors and their dot product. This display is convenient for determining the angle between any two vectors in three dimensions.