I'll give the beginnings a shot then, but is the Eden storyline something that updates with patches then? Since this is the first time I'm caught up hahaha
Ah then your question is understandable xD
I'll tell you how this usually works per patch:
X.0: MSQ with ending, 2 Trials in EXtreme, 1st part of the Raid (4 bosses).
X.1: MSQ keeps going, 1 Trial in Extreme. Usually the the Mistrel's Ballad version of the final MSQ Boss. 1st part of Alliance Raid.
X.2: MSQ keeps going, 1st trial + EXtreme of a new storyline, 2nd part of the Raid (4 bosses)
X.3: MSQ ENDING where the expansion has the "REAL FINAL BOSS" in Trial form and starts moving to the next expansion plotline+ EXtreme, 2nd part of the Alliance Raid.
X.4: MSQ keeps moving to the next expansion, 2nd Trial + EX of the Trial Storyline, 3rd and final part of the Raid (4 Bosses).
X.5: MSQ literally moves to the next expansion and ends with "to be continued", 3rd Trial + EX of the Trial StoryLine with ending, 3rd and final part of the Alliance Raid.
This could change but has been the same since HW, maybe they add something in between like when they added Rathalos out of nowhere during Stormblood.
For you to understand better the terms...when we say Raid we mean Bahamut, Alexander, Omega and Eden. When we say "Alliance Raid" we mean Crystal Tower, Ivalice or the new NIER stuff for 24 players. A trial is just a 1 boss battle, usually a primal.