The TRUST has been out for about a month now. The FAA sent out a notice that the testing providers had been selected, but you had to read further to determine that the test itself was also available.
The FAA page on the topic explains who needs to take the TRUST and what proof needs to be carried on your person. Interestingly, the requirement to take the TRUST is not a recurring one. The only time you need to retake it is if you lose your original certificate. The testing providers do not save your certificates, or your information, so remember to keep a digital copy somewhere safe.