Read the text and answer the question below it carerully!

How to Operate Manual Camera

1. Open the back of the camera by pressing down the latch typically located on the right side of the camera.
2. Select and load the film. Close the back of the camera and wind the film onto the spool until the frame counter on the top left of the camera reads "1".
3. Set the film speed using the dial located on the top left of the camera.
4. Set the shutter speed on top of the camera and the aperture on the camera lens using either a built-in or handheld light meter to determine the correct settings.
5. Slip the flash, if you're using one, into the hot shoe on top of the camera, and turn the mount on the bottom of the flash to secure it. Turn on the flash and set the shutter speed at 1/60th of a second.
6. Choose a lens and attach it by aligning the dot on the camera body with the dot on the base of the lens. Some cameras have a lens release next to the lens. Turn the lens base until it's firmly attached to the camera body.
7. Look through the view finder window and focus the camera by turning the focusing ring on the lens.
8. Frame the image and press the shutter release on the top right of the camera to take a picture.
9. Wind the film to the next frame.
10. Rewind the film when you reach the end of the roll, open the back, and remove the film.

"Choose a lens and attach it by aligning the dot on the camera body with the dot on the base of the lens."

What does the underlined word refer to?