Make sure that you have paired the CT10 with your device, following the instructions that came with the CT10.
Test it by opening Notepad, set your cursor, and scan an item. The UPC number should then appear on-screen. So far the keyboard should not have shown.
Show the Keyboard (OSK mode)
To bring up the keyboard and have it appear automatically at this point, pull the trigger twice in rapid succession. Make sure the trigger is fully released each time. You only need to do this once to set the CT10 into OSK mode.
With the CT10 paired to your device, launch Prep & Pantry. Tap on the 'enter barcode number' field and scan your first item. You will see the barcode number briefly appear before you are taken the the next window.
If you are scanning a new item that is not in the UPC database you will need to enter the item name at this point. Tap on the 'enter item name' field near the top of the window. The keyboard should appear at this point if you have set OSK mode correctly. If it doesn't appear, just do the quick double trigger pull, as explained above, and the keyboard will appear as normal.
Make sure your CT10 is fully charged. I have found that getting it into OSK mode is very difficult, if not impossible, when the battery is low.
The full user manual can be found here.