What method did you use? What errors did you have?
The import script reads a mysql database. You can’t use CSV files. What suggested that you could use CSV files?
It works like the other import scripts. And the start of the file includes this:
So you need to have a mysql database that the machine that’s running the script can access, define those ENV variables and run the script as it says.
You can look at some other examples in Migrating to Discourse - Discourse Meta. They all work about the same.