imputting new inventory

Apple School /or/ Business Manager (ASM/ABM) -> Link Your Jamf MDM Server to your ASM or ABM account and you will be able to enroll the iPads via DEP.

Document located here - http://docs.jamf.com/best-practice-workflows/jamf-pro/enrolling-devices-automated-mdm/Integrating_with_Apple_Business_Manager_and_Apple_School_Manager.html

or you can always use the Mut!

https://www.jamf.com/jamf-nation/third-party-products/620/the-mut

ALSO! I take it you have Jamf Pro? Have you done a Jumpstart? Your Jamfbuddy can help you out with this. They can also do a remote iOS specific overview to help you out!