Two modules, 27 questions and 32 minutes each, run back-to-back. How you do on Module 1 decides whether Module 2 is the harder or easier form — and, as on the real test, you won't be told which. You get the same tools you'll have on test day: a flag to mark questions, an eliminator to cross out choices, a question navigator, a timer you can hide, and passage highlighting.
Best taken on a laptop or tablet in one sitting — like the real Bluebook test, which won't run on a phone.