In ZAM 7.5
Go to the Asset Inventory tab

There's three main menu items on the left-hand side

System List
Custom Reports

Expand the Reports (2nd one)
Expand License Tracking
Now select: "By Product" report

Mine shows nothing.

But if I go to Asset Management tab -> Software Management
I can go to the Reports section and run any number of the reports and
see licenses and workstations counts (ie, Software Compliance reports,
or License Allocation -> Current Allocations, etc.)