Read the AIC ! its been writen above and I will just make it clear that it is the LAW that you must have it or the poolys or jepp charts for the rally with you in the aircraft.
Some years back it took me a wile to pick up the ATIS message as some one kept trying to talk to it !.
On the whole the standard of airmanship is very high at the rally but it only takes one pilot who has not taken the time to read the instructions in the AIC to be a real danger to all around him.