The answer above by Christian is the correct approach...
There are a lot of options for the REST HTTP URL calls to MII, direct to the Runner engine can be synchronously or asynchronously triggered; documentation for this interface is located here:
Transaction Calls Using URLs - SAP Manufacturing Integration and Intelligence - SAP Library
You can also call into the HTTP Message Services listener layer which can allow you to batch requests or trigger the transactions immediately. It's an additional layer of monitoring but will enable routing based on a URL parameter or message contents along with message processing status tracking; documentation for this interface is located here:
Message Listeners - SAP Manufacturing Integration and Intelligence - SAP Library
Sam
PS: Generic help documentation for MII is here: SAP Manufacturing Integration and Intelligence 15.0 – SAP Help Portal Page