If you Google the terms "vernal equinox" or "autumnal equinox" you will find Web pages that describe this far better than I can, and they'll include illustrations that will help.
I mean, if I were to step outside with the coordinates of a star, how would I go about locating that star?
let me offer a shortcut: Get yourself a starchart, or a book like Norton's Star Atlas. You can find these at reasonable prices online. Alternatively, you can download a free planetarium program like Celestia or Stellarium, which you can use to print or display your own charts.
Look for the charts in your book which show the ecliptic (path of the Sun, Moon, and planets through the sky) and the Celestial Equator. On those charts, the Celestial Equator will be marked with the hours, minutes, and seconds of Right Ascension along the borders of the charts. In fact, most charts show the RA markers along the horizontal borders of the charts and the DEC markers along the vertical edges.
Alternatively, if you have a planisphere, rotate it so that it lines up Noon on the inner circle with March 21 on the outer circle. You'll see a line bisecting the word Noon and running up through the star chart to the rivet on which the chart turns in the elliptical window. That line marks 0:00:00 RA very nearly. You can work out the positions using RA from that point.
Once you know the names of some of the stars in the sky (and a planisphere is a great tool to help with that), you can look up their RA and remember one bright one visible at night per season. Then, using only those four stars, you can find your way around the sky fairly easily.
It also just so happens that if you stretch out your arm to the sky and then spread your pinkie finger and forefinger as far apart as you can, the measure of the sky so marked will be about 15 degrees, or one hour of arc (360 degrees, divided by 24 hours in a day, = 15 degrees of sky per hour).
So, to estimate an RA of three hours west of one of the stars you've memorized, you just estimate three times the span of the distance between your pinkie and forefinger "projected against the sky".
I think you'll find it far easier just to look these positions up in a star chart.
Hope that helps!