I finished it last month, it's ok. You'll be fine, just study and do past exams you'll be alright
You'll have a multiple choice exam of 60 questions, you've got to get something like 48 correct to pass.
There's an 1hr 20 minutes written exam but don't stress about it. It's 6 questions with relatively short answers so you'll have plenty of time to finish it
Then you've got a selection pictures showing various faults that you have to code C1, C2 or C3, if in doubt code up from your gut instinct but tbh you can't fail this part unless you miss an obvious danger and they're all pretty obvious.
The practical exam is an EICR and an Initial Verification mixed into one with faults switched in. If you follow the standard testing procedure in guidance note 3 then you won't miss anything. The faults I had were open circuit on one of the phases in the Motor and I had a broken switch line and some dodgy readings.
To be honest the most time consuming part for me was filling out all the paper work for the condition report, you've got to code all the faults you found and find the applicable regs number. Made me realise I'm not as clued up as I thought
As much as I hate to admit it, it's severely watered down since the real 2391, you're allowed to take your books into the exams with you so you'll always have something to fall back on if you get stuck.