Replacing the converter is not always just plug it in. In our 2008, some basic wiring knowledge was helpful. Your trailer may have the same arrangement.
The black cover over the converter and fuse/breaker panel screws onto the OEM converter. I had to cut the plate off front of the OEM converter underneath the cover so I'd have something to screw the cover to. This was not enjoyable. Figuring out the correct wires to attach to the new converter was not very hard, but I have been doing my own electrical work for decades.
This doesn't mean you can't figure it out, but you may have to call the company for advice—or post here.
Like Bob we have an Iota.