Looks to be sorted by event numbers, which seem to be assigned first by event type (Minis, RPGs, etc.), then by host group (CDT, etc.), then by event title (kinda), then by time.
Event starting time is listed in column F of the sheet. All the Catalyst RP events are scheduled for 4-hour slots with an hour break between. Basic schedule has slots starting 1200/1700 Wed (3 June), 0800/1300/1600 Thur-Sat (4-6 June), and 0800/1000 Sun (7 June), so you could play 12 games if you wanted (2 Wed, 3 Thur, 3 Fri, 3 Sat, 1 Sun).
The Catalyst RP schedule starts with event #6281 (line 3352 of the spreadsheet):
CMP 2012-01 through -04 (London Falling)
CMP 2014-01, first of the Boundless Mercy arc from last year, offered only once.
CMP 2015-01 through -04 (Tennessee Suite), which debut at Origins.
All the season 5 SRMs except Critic's Choice (05-02) (Not sure why that one got left out other than maybe just an error during event submission, but each of these is offered only once.)
All the season 5 SRMs, including the last two which debut at Origins this year: SRM 06-05 Healing the Sick and SRM 06-06 Falling Angels (written by me)
A whole bunch of Into the Shadows and The First Taste, which replace the old Welcome to the Sixth World event (Into the Shadows is chargen, First Taste is a mini-mission.)
After the Gravastar arc (Cosmic Patrol) and the Unity arc (Valiant RPG) we have the first Prime Mission: PM-01 Killing Pawn. (Be careful. As I understand the prime runner rules and the Missions FAQ, playing a PM makes your character a prime runner, and prime runners are ineligible for regular Missions play. But it's the only way to play your old characters from Seasons 2-4.)
