How do I configure Modbus RTU on an MI HMI talking to a network of Modbus slave MI HMIs?

Set up a project containing multiple HMI's (see file menu 'multipanel'
option in Config Manager). The first unit is the master, running Modbus
RTU, the others are the slaves running Modbus slave.
Set up the ports with parameters which match.
Set up several devices on the master's port, one for each slave, giving
each one a device address matching the slaves device address.
Set up a single device on each slave, with a unique address, which is
the slaves own address.
Configure the data items on each slave, which it is to provide to the
master (bits and registers)
Configure all of the data on the Master which its requires from the
slaves.
The network should be set up as RS422 4wire. It is not recommended that RS485 two wire comms are used.
The 'paneltopanel' protocol can also be used, which will work on RS485
two wire. However, it must be noted that this protocol will only work
where all devices on the network are MI HMI's.