Migration ralph to new server

I am trying to migrate a ralph installation to a new server.
Following this instructions Link I have the new server functional.
The source and destination versions are as follows:
Origin: ralph --version 1.8.18
Destination: ralphctl --version 1.8.19
In the origin I exported the data in the following way:
ralph dumpdata -o backup / ralph-dumpdata.csv
In the destination when importing it like this:
ralphctl importer -t file /home/alext/ralph-dumpdata.csv
I get the following error:
CommandError: You must select a model

Am I doing it the right way?
In case of yes, how do I select all the models since I need to import everything?

Thank you in advance for the help or documentation links that you can send me to address the issue.