A lot of this is answered in the crash course, here https://www.reddit.com/r/FoWtcg/wiki/index
As for Sets, the Fourth and most current "Cluster" is the "Lapis Cluster". This cluster only just Started in September 2016. The Cluster consist of, L0 - Lapis Starter Decks (aka SDL) L1 - Curse of the Frozen Casket (aka CFC) L2 - Legacy Lost (aka LEL)
The previous (Third) cluster(Still in rotation) is the "Alice Cluster". That cluster Started on July 30th, 2015, and finished releasing all of its sets by July 29th, 2016. The AC consists of, A0 - Melgis Faria Starter Decks (aka VS01) A1 - Seven Kings of the Lands (aka SKL) A2 - The Twilight Wanderer (aka TTW) A3 - The Moonlit Savior (aka TMS) A4 - Battle for Attoractia (aka BFA) A5(?) - Vingolf 2: Valkyria Chronicles ( aka VIN002)
The most current format in FoW equivalent to MtG's Standard is "New Frontiers". Which is the most 2 recent clusters, which are currently the two I listed, Alice and Lapis Cluster~
There isn't any specific date given as of yet on when/how early AC will be rotated out, but generally a cluster takes about a year to release all of it's set, but lasts for about 2 years~