The developers are currently streaming a 4-hour gameplay session on Twitch, showing off what the early build of Update 1.4 on the PTS that will go live tomorrow is capable of. Talking about the PTS in particular, they have already started to send out Early Access keys for the Uplay or Steam platform.
Remember that only PC players who applied for the ETF will be able to play in this first technical test. All other PC players will be able to join next Monday on September 26th. The download size of the additional client is around 40 GB big. Don’t forget to provide feedback in the official forums and that there is no NDA!
For more information about the PTS, check out the official FAQ.