if you haven't seen Gundam and wanna watch the Hathaway movies and actually understand the 50 year masterpiece of the Gundam Universal Century timeline, you gotta start with the original show. Skip the entire series and just watch the 3 original Mobile Suit Gundam complation movies to save time. Right after that, watch Gundam: The Origin. It's a prequel that's all about Char Aznable and his rise and goes crazy hard. You can watch the Mobile Suit Zeta Gundam compliation movies to save time, but I really recommend watching the whole series to get some of the side plot elements. Alot of the characters from the original show reappear and old friends are now new enemies and vice/versa. It's quite good. After that is ZZ Gundam, which if you're just getting up to speed for Hathaway, I'd say is optional, but is great for getting the whole picture leading into the final-ish movie. Then you gotta watch the Char's Counterattack movie where you actually get introduced to Hathaway Noa and can see the all of the fallout that directly leads into the Hathaway movies. For the side stories: If you want a nice diversion, and wanna see a Gundam show that in Vietnam and NOT in space, watch 08th MS Team. It's quite excellent and takes place concurrently with the OG show/compilation movies. If you want space battles over an absolute banger of a Jazz and Blues soundtrack, watch the 2 Gundam Thunderbolt movies. While technically a side story, 0083: Stardust Memories takes place between the original show and Zeta and is basically Top Gun with giant mechs and explains why the earth is now the bad guys in Zeta Gundam. If you want Gundam, but a Christmas story, watch 0080: War in the Pocket. It's only 6 episodes long and focuses more on the civilian perspective. There's also Gundam Unicorn which takes place 3 years after Char's Counterattack and has fucking crazy soundtrack and an awesome story.