There are varying timelines on how quickly you can complete your class set up; the more classes and categories you have, the longer it will take. Once you have your classes imported, category structure in place, entry fields assigned plus all checks on the Competitions Set up Checklist, you are ready to open your classes to the public. 

It is useful to proof your bulk class import once in the system - you can do this by running off your schedule, with all the fields displayed.