The schedule for the Autumn Season playoffs is announced on www.guildwars.com
The initial playoffs start 11 am PDT Saturday October 21st. The semifinals start the following day, Sunday 22nd 9 am PST. The semi-finals start 30 minutes after the semi-finals are done, around 12-13.30 PST.
You find all the nececcary info on the Autumn Season Ladder Playoff Schedule