Follow the UC timeline and or release order.
0079 is Mobile Suit Gundam the first in the series taking place in the 79th year of the universal century.
Zeta is the squeal to 0079, seven years later and was the second series
ZZ continues right after the events of the Zeta finale
Then if you continue down the UC timeline, there Char's Counterattack.
Turn-A is sorta complicated but its at the end of the Gundam Timeline (like 1000's of years past the other series)
Outside the UC timeline, Gundam 00
Man God can recommend Gundam OVAs (since there are alot of them), but one I can is Gundam Thunderbolts which is a side story during 0079 and Gundam The Origin which tells the story and origins of the main villian/rival in 0079 Char and his sister Sayla, along with other events building up to the events of 0079 (Rise of the Principality of Zeon/Rise of the Zabi's, creation of the mobile suit, Amuro's days on Side 7, the creation of Gundam)