Information on various judging postions can be found at NorCal Odyssey Judge Positions. While this is more specific to the World Final competition, the descriptions apply to other tournaments as well.
As a judge, you need to be familiar with all the problem clarifications provided to the teams. The public clarifications can be found at: https://www.odysseyofthemind.com/clarifications/ . In addition, there are "private" clarifications provided to teams. Private clarifications are those that are specific to a solution, which should not be revealed to other teams. Your problem captain can provide you with those clarifications, as and when they are available.