Answer:
You must have the object centered before you change objectives to increase the magnification, because the field of view becomes smaller; if the object is off to the side, it may disappear when you go to higher magnification. For best viewing at high power, white light is essential.
Step-by-step explanation:
Start by turning the revolving nosepiece (turret) so that the lowest power objective lens is "clicked" into position. The lowest power objective is the shortest one. This objective is the easiest to focus and center the image in the field of view.