Star viewing and finding the star constellations by declination is fairly simple. Declination is approximate to latitude on Earth. So if your latitude is within about 80 degrees of a constellations declination, you should be able to see it at some point during the year.
The longitudinal angle is called the right ascension (RA for short). It measures the angle of an object east of the vernal equinox point. Since a full rotation of the sky takes 24 hours to complete, there are 15 degrees in one hour of right ascension(360degrees/24hours=15degrees).
The latitude equivalent to right ascension is declination.
Declination is listed from zero degrees to 90 degrees North, which is above the celestial equator. And zero degrees to 90 degrees South or below the celestial equator.
Northern degrees are denoted with a plus sign(+), and Southern degrees with a minus(-).
The month listed on the constellation page is the month during which the constellation is highest in the sky. Remember though that each constellation can be visible to the sky gazing beginner during several months. Of course, some can't be seen from certain places at all.
In the northern hemisphere, those of us above the equator, a constellation is visible to the star viewer for a larger part of the year as the declination goes up.
So the “Little Dipper”at a declination of +70 degrees is visible most of the year.
In the southern half of the planet, the opposite is true. Those constellations with a smaller declination or larger minus number are visible longer.
So Crux the “Southern Cross” with a declination of -60 degrees is visible to most people “down under” most of the year. A good amount of people in the northern hemisphere can see it occasionally as well very low in the sky.
Of course where I live at about +39 degrees N latitude it is never visible at all. Just as the North Star Polaris, declination +89 degrees is not visible from the southern hemisphere(you may glimpse it if your near the equator).
Once you find your right ascension(RA), and declination(DEC), you can use the mini-astro viewer to see the sky over your area.