Robert6156 --
When you open a master project from Project Online, Microsoft Project automatically opens every one of its subprojects. If the subprojects are not fully expanded, you should do that in any task view, such as the Gantt Chart view. Then you can
apply the Resource Usage view to see all of the resource assignments across all of the subprojects in the master project. You might want to temporarily insert the Project Column to the left of the Resource Name column to help you to identify the subproject
to which each resource assignment belongs. Hope this helps.
Dale A. Howard [MVP]