Every project you create in CoConstruct will always have a schedule. At a minimum, the schedule page will consist of at least one task, and if you created a project from scratch, you may see a placeholder "Create schedule" task.
You can replace your existing schedule with a new template by selecting the "Copy Template" link at the top right of the Gantt, Calendar or Task View.
To delete your schedule and start from scratch you can use the Ctrl+Shift keys to select a full range of tasks and select the "X" icon at the top to delete all selected tasks. You can then manually add in your new list of tasks. Remember, that you'll need to add back at least one task before publishing your changes to the schedule.
If you're not ready to start using the schedule yet, push the dates out into the future so tasks do not show up as overdue.