If you want to add a new detail report in Alloy Navigator, you must create it outside Alloy Navigator using Microsoft Report Builder 2016 or later, and then import your RDL report file to Alloy Navigator.
To import an external RDL detail report file into Alloy Navigator:
Open the details window for any object of the target class.
For example, if you want to change a detail report for
Work Orders, open any Work Order.
On the Module menu, choose Print > Manage Reports. The Manage Reports windows appears.
Right-click any detail report and choose New from the pop-up menu. Alternatively, you can choose New > New from the main menu.
Browse to the source file and click Open. The new report appears in the Manage Report window, its name is same as the name of the source file.