How can I add the same Data Layer to more than one Incident map?
Using the Data Layers > Data Layers admin page navigate to the bottom and choose the Incidents tab. On the incident tab choose the Add button and you can then select another Incident (project) that your Data Layer will be associated to.
You can also define if the Data Layer should be linked to a specific Base Layer e.g. the Graffiti Data Layer will only display when the OSMM Base Map layer is shown.