Most constellation maps, or star charts, are circular and labelled with the four cardinal directions and the names of constellations and their major stars. Star charts are also marked with the time of year they represent as well as the viewing latitude they represent.
When using a star chart, hold the chart up in front of you, and rotate it so that the direction you are facing is on the bottom of the chart. Then, hold the chart up in front of you, and compare the stars in the sky to the stars on the map.
Star charts represent constellations and stars when viewed from a specific latitude, so depending on how above or below that latitude you are standing, the stars shift accordingly. Because the earth is constantly rotating, star charts are only accurate for a certain time of the year, usually divided by month. Star visibility also differs by the time of day.