On the first board they score the applicants and rate them from #1 on down, they then select a certain number, which they decide at the time, from that list to award scholarships. The rest of the applicants are rolled over to the next board.
Now comes the second board, all the new applicants, the ones that did not have their applications done for the first board, are given a score by the board. These new applicants are pooled together with the applicants that rolled over from the first board. They now make a new list by using all the scored applicants again starting at #1 on down. This means that the first applicant not selected from the first board will not simply be the first applicant on the new list. New applicants being reviewed for the first time may score higher putting them farther up the list.
There are a lot of applicants that do not submit in time for the first board but make the second board. While a first board rollover is getting a second look, there is not much of an advantage due to the large number of new applicants for the second board.
The third board operates the same way, although there are usually not as many new applicants for the third board. The third board would be the place that you might have a better chance due to the numbers.
Hope that made at least a little sense.