That depends, ultimately, on who will be processing the production orders. Ideally, all those who process production orders will learn/understand the desktop version as well as iPad to fully understand how everything works in unison. It is not uncommon for some clients to have managers who understand the desktop version and specifically only train others on the iPad. This allows more simplicity for those processing production to use an iPad rather than having to learn both. But for this to be successful the managers, at the very least, must still understand how to troubleshoot/process in the desktop version as needed.
For other clients, they may only have one or two people processing production orders, so mastering desktop processing first makes more sense, followed after with learning the iPad production process.
Regardless, it is essential that multiple people at the facility understand the desktop production process as well as iPad's production process.