Adding IO modules to your HMC project is as simple as allocating the correct module part number to the correct slot under the "IO Allocation" folder in your project.
Receiving a mismatch error on boot up could be due to the following reasons:
1) a module is physically present in a slot for which a different module is allocated in the project.
2) a module is physically present in a slot for which no module is allocated.
3) a module is in the correct slot, but is not powered. Make sure that the module is supplied 24VDC of power to the terminal block labeled "24V". The module is not powered through the connection to the HMC.