Flying (moving up and down)
You'll need to use the keyboard to fly up and down. On the numeric keypad, the + (plus) key
moves you up, and the - (minus) key moves you back down again. You can hold these keys
down to keep moving up or down, and you can use them
in combination with the CTRL key to move faster or the SHIFT key to move through objects.
Note that on laptop computers, which don't have numeric keypads, the + and - keys are usually
accessible via a combination of a function key and some other key on the laptop keyboard.
Using the plus key turns off gravity until you touch the ground again. While gravity is off, you
can continue to fly up or down until your feet touch the ground again. Press the minus key until
you touch in order to turn gravity off. While you're in Fly mode, you'll notice that you'll coast
more before coming to a stop in either the horizontal or vertical direction. If you want to come
to a sudden stop, you can press the "5" key (the "Stop key") in the center of the
numberpad.