From within CostGuard click on Inventory/Counts/New
Choose the location you want to add those items to, then click on Enter Counts.
At the bottom of the screen click the + button. This will bring up all your items. Choose the items you would like to add.
Make sure to check the box Show All Items.
Also, uncheck the box that says Close Dialog
You can either enter a count number or leave it blank. If you leave it blank and save the count it will just add the item to the location!