In AutoCAD Architecture 2023 toolset, project sheets are collected in sheet sets or a project. A sheet set allows you to have common publishing setups across a number of sheets.
When you create a new project, a unique sheet set is created for this project. The project sheet set is displayed on the Sheets tab of the Project Navigator.
Project sheet set in AutoCAD Architecture 2023 Toolset Project Navigator
Only one sheet set can be associated with a project. You cannot change the sheet set for an existing project, but you can change its properties.