the practice test is here
Basically you should aim to get
all the questions right
and quickly.
I assume you are penalised heavily for getting any questions wrong, so the overall scoring would likely be something like:
* 100% correct and elapsed time 60% - 98th percentile (say)
* 100% correct and elapsed time 99% - 70th percentile (say)
* 93% correct (one wrong) and elapsed time 30% - 69th percentile (say)
So you need to be able to read quickly and get everything right.
There is something called test-retest reliability aka the standard error of measurement, and for me I'd hope to get 100% on this particular test, BUT it's obviously possible for me to get one or even two wrong as a result of this inherent randomness, which would likely lead to my rejection without this really being a genuine reflection of my ability.
However I do read very fast, so IF I get it all right, then my percentile will be very high and I will be advanced to the next round.
I don't know how difficult others find the test so I might be some way off on the percentile range for getting all questions correct, and it's also possible that I got one wrong and was nonetheless ranked in the top percentiles due to speed being co-prioritised alongside accuracy, but I suspect not.