This is assuming you already have licenses set up within FNMS.
1. Add or create the purchase order in FNMS for the true-up items. Be sure to have the SKU number 2. Process the purchase order 3. Associate the true-up counts and product names with the licenses you already have in FNMS. 4. If you don't have a license, create one from the purchase order line item.
If you don't already have licenses set up in FNMS, the quickest approach is just to import the MLS straight into the system using the MLS import on the purchase import page. It will automatically create licenses and link the summary entitlement details. You can get there using the one-off uploads in the data inputs menu.