I’m a newbie Gundam modeler myself. I have one unbuilt (an MG EZ-8 from ‘8th MS Team’) but I’ve built several snap-together kits from the Gundam Wing universe. The Gundam story concept covers 3 or more ‘universes’ –unrelated story lines that use the Gundam robot.
The original is about a time in the future when there are several large space colonies at various Lagrange (spelling?) points in Earth orbit. One set of colonies wants to declare independence from the United Earth Federation government and a civil war starts. The rebel space colonies use ‘Zaku’ mobile suits and the Gundam enters the story as the first mobile suite made by the Federation. Several series (most of the Gundam series, I believe) are based on this storyline and spans many years. The story purposely never gives a definitive good guy/bad guy label to either side.
Gundam Wing is about a 5 Gundams, each from one space colony, coming to Earth with it’s pilots and performing subversive acts against the Earth government in the name of independence for the space colonies.
The G-Gundam universe is about various Gundam designs being used in a tournament style combat.
Almost all the Gundam stories deal with political power struggles, the horror of war and personal loss and other rather heavy subjects. I found the original story line to be the best with the ‘8th MS Team’ and ‘Stardust Memories’ my favorites from them.