Manage > Software Catalog
Select a Managed product or make a product managed
Select the Meter/track usage tab
Add an associated program if none are listed, then check 'Turn on metering / usage tracking for this application'
On the same tab, enter a number in the box for how many days to look at for use, for example, used in the last 30 days, 90 days, etc.
On the licenses tab, enter a purchased license.
Within the Software tab, go to Managed Software, and select the managed software you're working with. The right pane shows your licensing usage against licenses owned, and whether you can save money by renewing for fewer licenses, or whether you have a potential cost in order to true-up on licensing. You probably want to use the usage data to harvest in either case, because that only saves you even more money.
Does this make sense? To add licenses, you must own Asset Management Suite. But you can do everything else listed without entering license data, and you'll still get license information on the same page I mentioned above. The difference is you will "own 0", so your usage number will automatically show you as over.