There are many reasons why someone may want to create a new campaign. It could be simply to seperate two seperate gaming groups (for which you Judge/GM both) and would like to have each one seperate so you can keep track of active effects/combat/etc all in that one contained campagin folder. Another reason why you may want to create more campaigns is to introduce a different ruleset for the campaign. Whatever your reason, here's the way to start.
From the Launch Judge screen, press the "Advanced" button.

Then you will notice a place to put a password and change the port. Also, there's a button that allows you to "Create Campaign...". This is the button we want to press to create a new campaign.

An Input Dialog box will appear, simply enter the name of the new Campaign and press the "OK" button.

Once you have done that you can then go in and modify the contents of this folder by adding in pictures and other resources to configure your campaign. Those resources will be located in the d20Pro install folder "d20Pro\judge\campaigns\". In MacOS, Alt+Click on the d20Pro program then "Open Package Contents" then navigate to "\judge\campaigns".
Goto the desired campaign that you wish to modify. Under that directory you will find the following folders:
| | game | stores the game state and game log. |
| | pref | stores game preferences. |
| | res | stores all graphical resources of the library and the installed ruleset. |
| | stored | stores map, creature, and handout data along with items and version. |
The "res" directory will contain the following subfolders:
| | CTR | stores the image files used for creatures. |
| | FLR | stores the image files used for maps. |
| | ITEM | stores the image files used for items. |
| | ManuallySpecified | stores classes, feats, marker icons, skills, spells, stats, and status icons. |
The "ManuallySpecified" directory contains these important files needed to allow use of them in the game:
| | classes.txt | contains all classes of the game system, and what spells each has access to. |
| | feats.txt | contains a listing of all available feats. |
| | skills.txt | contains a listing of all available skills. |
| | spells.txt | contains a listing of all available spells. |
| | markers.zip | contains image files for use as a map marker. |
| | stats.zip | contains html files for use in the creature's Mini Stats Tab. |
| | status.zip | contains image files for use as status effects. |