How to send variables to display in hmi siemens with modbus?

i'm using node-red to get some variables from a plc via OpcUa i'm using an iot2050,
I managed to read the variables I need now I should send these variables to an hmi panel to be able to read them on the panel,
I have to do it in modbus, but I've never used modbus, does anyone know how to do it?
thank you.