By default, attendees can book any sessions you allow, provided they are not double booking themselves. If the same session occurs as different times, or different days in your event, you may want the attendee to only book one.
Session codes can be used to prevent an attendee from booking the same session that may be occurring at different times. When two sessions use the same "session code", the system will prevent both from being booked.
Adding session codes
Go to Setup > Program > Sessions
Click to 'edit' one of the sessions that occurs multiple times
Enter a value into the "Code" field (remember this value as you will need to enter it again)
Click to 'edit' the session that is the same but occurring at another time
Enter the same code into the "Code" field
What will attendees see?
When an attendee attempts to book two sessions that have the same code, they will be given an error as below:
Below is an example of the registration process displaying this error. In this example, the two "Finance Workshop" sessions are using the same code, so only one can be booked: