I sat it in 2003... in the RDS with 000's of others... !!
I can't remember exactly what it consisted of, (I've done a lot of these type of tests in my lifetime), as far as I recall it was like the Clerical Officer exam for the Civil Service.. i.e. in 3 parts
1) 30 or so comprehension questions about several passages of text
2) 50 or so mathematical/computational questions
3) 20 or so job simulation questions e.g. you arrive on the scene of a fight - what do you do...
I do remember that the test was very straightforward and fair - nothing too challenging other than the time. They explained everything before each of the tests. There is no studying, per se, that could be done in advance. If your friend gets a good nights sleep beforehand and maintains their concentration throughout then they will be fine.