No, you don't need to know really anything for phase 2. It is just, that YOU create a flight plan, before you have to go through a test, where you have to discuss it with a partner and such stuff. So having at least seen a flight strip and knowing roughly what information it contains/should contain is somewhat helpfull (at least as far as my experience with the German ATC (DFS) Tests is concerned).
Phase 2 consists of 3 groups of 6 people being testet on 3 days.
So 15./16. and 17. have all the same tests, with just 3 groups of 6 doing the tests.
At least EC states, that Phase 2 consists of 6 person group tesing.. And Imke said as much as that they draft 18 people for their first block of Phase 2 in September.