Hold the binoculars near your eyes, but don't cram them up against them. Spread the binoculars apart until the center of each lens matches comfortably with the distance between each pupil of your eyes.
Locate the focusing ring called the right eye diopter and close your left eye. Choose a focal point by where you will be doing most of your viewing. For example, a bright star if you're doing astronomy or a distant tree if you're doing nature studies. Now, slowly turn the diopter until what you see on the right side comes into focus.
With both eyes open, use the center focus wheel to fine tune the image and you're ready to go!