The default design when you start a job is attached to timber fascia, at the top of the structure. The attachment is shown by the yellow bar at the top of the job.

To unattach the structure and make it Freestanding, left click in the yellow area at the top of your structure

This will open a pop-up which allows you to modify the attachment by clicking UNATTACH.

The software will remove the attachment and automatically add corner posts for support

In this feature you will also be able to change your Gutter settings and add Overhangs.

If you are designing a gable structure, the gutter that was included in the attachment will also be removed, so you will need to add that back in