It's in the team.db file.
Take this as an example for the Broncos:
Count 21 places forward from the letters BRI, and you should be on 5B. The next hex value is 02. These numbers determine who's the captain.
If you do a search in the player.db file for 5B01 (hex values search), it should come to Gorden Tallis.
Take note that in the player.db file, 5B01 is the FIRST hex value to have any significance in the values after his name finishes.
Now, in the team.db file, the next digits are 1601 (Ikin)- this is the first place kicker.
The next are 5501 (Lockyer)- 2nd place kicker.
Next is 7500 (De Vere)- 1st goal kicker.
Then 5302 (Swain)- 2nd goal kicker.
Now it starts into the player line-up.
5501-Lockyer
7500- De Vere
5D02- Tate
4B00- Carroll
3201- Kelly
etc.
Just say you wanted to put Casey McGuire in the centres in place of Carroll.
Do a search in the player.db files for McGuire (text string).
You will notice the first values after his name are 7E01.
Now go to Carroll's values in the team.db file (4B00) and type in 7E01.
Now find 7E01, and type in 4B00.
Casey McGuire will now be in the centres in place of Tonie Carroll who will be on the bench.
I hope this is easy enough to understand!