Begin by clicking on the "Back Office" button on the home screen.
Under utilities, click on "Configuration".
Now, click on "OrderCraze Config".
This should automatically take you to the categories button. Under the sort column you can sort categories by organizing the numbers. I find it easiest to organize the numbers by tens. For example, 10, 20, 30, etc...
You can arrange the numbers how you want if you decide you want the categories sorted differently. Be sure to hit "Save & Sync" at the end to save you work.