If it's available it should be in the App Library (https://www.tracerplus.com/mobile-apps) on the TracerPlus website. If not that exact app, there's bound to be similar apps available for download that you can use as a starting point and then further tweak to your needs.
Use this demo app to quickly test reading RFID tags with your Zebra TC20 and RFD2000 RFID Sled. This app also doubles as a room inventory audit scanning multiple RFID tags to a selected room.
Also, the following Asset Tracking application shows how to setup a grid control that shows expected items in a location. This could help you setup am RFID form to show scanned versus not scanned RFID tags:
Asset audit application template allowing you to input a location to display the assets expected in this location. As you scan assets they will be removed from the list, verifying they are in the correct location.