Cut off everything outside the outermost circle on both plates. Bend the pin so the point lies flat against the back of the bottom plate, and tape it there. Your assembled planisphere should resemble the figure at the top of this page. To see what the stars look like at a particular time on a particular day, dial the planisphere so that the time on the inner ring lines up with the date on the outer ring. The entire portion of sky visible at that time on that day will appear through the window.
Bigger dots represent brighter stars.
If you hold the planisphere over your head, it will show you basically what you see in the sky. The oval represents the horizon. Stars further away from the edge appear higher in the sky. The planisphere only shows stars brighter than magnitude 4. Then you can try to identify dimmer stars and constellations by their relation to the stars you already know.