Thanks Lyn. I think I understand.
I've had a look at the Classic track dialogue box and I know how to get a track working with the DXi and plugins etc. I am using a Yamaha USB midi interface which is listed in Options>Mididevices when its connected(I'm not at home at the moment so can't check). I presume it'll show up on ports 1 through to 16 on the Classic track dialogue if I have it selected in Options > Mididevices. I'll give it a go. I'll be an expert soon!!