The Start Date and End Date from Codebeamer are exported to the Start and Finish properties to MS-Project.

The duration fields, such as Estimated Hours and Spent Hours, are exported to the Duration and Actual Duration fields. The MS-Project will automatically calculate the % Complete value from the Actual Duration and Duration ratio.

Any tasks in MS Project can be in Manual Scheduling or Automatic Scheduling mode. This setting affects how the MS Project schedules and handles tasks.

The Manual scheduling mode gives users complete control over how the tasks are scheduled. For example, the user can set any durations, dates, or dependencies manually, which are respected by MS Project and will not be updated automatically by MS Project.

The Automatic scheduling mode enables MS Project to automatically calculate and update the dates, durations, and schedule from the dependencies between tasks and calendars.

For more information see: Manual vs automatic schedule: How scheduling works in Project?

Using MS Project export and import, you can control how the exported task will be scheduled. The following options are available: Manual schedule for all tasks, Automatic schedule for all tasks and Smart: Use tags or determine from item start/end dates.

If using Smart mode, the task will have an automatic schedule if the work item has the tag MS-PROJECT AUTO_SCHEDULED added or the Start Date and End Date of the work item is empty.

The MS-PROJECT AUTO_SCHEDULED or MS-PROJECT MANUALLY_ SCHEDULED tags are added during the import from MS Project to keep this information for future updates. You can also add these tags manually if you want to control how each task is exported.

That is how the tag looks like on the a work-item: