When an RFID handheld reads an RFID tag, it receives back an RSSI (receiving strength signal indicator) value. This value can be used to approximate the distance that the RFID handheld is away from the specified RFID tag (and thus the associated item or asset)
To invoke the find item option, on the Inventory Scan page, swipe right to left on the desired RFID tag. Then click on the green eye icon. This will navigate you to the Find Asset page.
Depending on the RFID device that you are using, you can either use the physical button / trigger on the RFID device or Start / Stop button on the screen.