The entire path is shown in Usage at --help

[joserobjr]

Z:\teste cli>java -jar Java2Nukkit-World-Converter-1.0.0-cli.jar
Usage: java -jar /Z:/teste cli/Java2Nukkit-World-Converter-1.0.0-cli.jar [-h] from-dir to-dir [-r regions]

  -h, --help                Prints help
  from-dir                  The world Java Edition world directory
  to-dir                    The location where the Nukkit world will be created
  -r regions                A list of region positions that will be converted. Example: -r 0,0;-1,0;-1,-1