Start with the original show if you can stomach early 80s animation, and early 80s Japanese sensibilities with regards to gender roles and stuff. Mostly just because it's the easiest entry to get a hold of without resorting to piracy. The original show "Super Dimensional Fortress Macross" should be free on Amazon Prime. The next entry to the franchise, "Macross Plus" you can watch on Prime if you rent it. That show takes place 30 years after the original as humanity sets out to explore and colonize the stars.