I'm just completed it. It's an online trainee simulation, basically a mixture of video response, writing, and SJT. The video responses are timed, but not for anything else. There are also some motivational video questions. I messed up quite a few questions unfortunately so don't think I'll be getting it
I think just remember to review all the resources they give you, don't panic when it's timed, and just absorb and analyse what you can.