Insert from device is a new command introduced in 13, to use the new command you will have to update.
Take a look at this link for another method.
I just recently updated from 12 to 13. When I was using 12, I got around the fact that Filemaker Go 12 didn't have a barcode scan from camera by using Icody and using a call back script.
Go to https://appthology.zendesk.com/hc/en-us/articles/201053788-Guide-to-iCody-s-Callback-Scripting and check it out. Icody is kind of expensive but it worked wonderfully!
In FMPA12 & FMGo12 I used CNS Barcode app with the open URL script to scan a barcode and then have CNS pass back a parameter (read barcode data) to another script to update the field.
While this worked well, it was a little off putting for the user seeing the applications back and forth. There was also the issue with the added time it took ... in short it wasn't integrated and seamless.
FMPA13 brings this insert from device script step and quite a few other features that have made the FMGO13 layouts and functionality far more usable for the end users. Slide controls, popovers and customisable keyboards not to mention the barcode scanning brought a more polished and integrated user interface for the user.
The upgrade to FMPA13 was well worth the cost not just for this insert from device feature but for all the other features it brought with it.