Great to see your so excited.
Piggyback means to mount your camera ontop of a telescope that is already mounted on an eq mount. This way you can guide you camera to prevent the stars from trailing.
Here is a simple formula to use to work out how long an exposure you can use and not get star trailing.
FL of lens/700= T sec for shooting near the celestial equator (declination 0)
FL of lens/1000 = T sec for shooting near the celestial poles (declination -90 or 90 deg)
So using a tripod with your camera and say your shortest focal length (FL) of your lens, 18mm (I'm assuming you have the 18-55 mm zoom lens) and shooting straight up will let you shoot for about 40 sec without trailing. Shooting at the pole will give you about 55 sec. 55sec at ISO400 and f/3.5 (I think that's the lowest f ratio for that focal length of that lens) will allow you to snap up the ol' Comet McNaught no problems, even now.
If you now switch to the 55mm you will only get 12 and 18 sec for the respective declinations.