You don't need to prepare, if that's what you're asking. Except by making sure your Hebrew is as good as possible.
There is a sort of intelligence test that tests spacial understanding. Which shape doesn't fit in the pattern, which shape is this other shape transposed, etc. The results are only applicable when the command staff determines if someone is cut out to be an officer. It's not the only criterion, of course, but it can disqualify someone. And no, you can't really prepare for that.
Mahal Nahal March '04 draft