these are all command line options that you can use. Some are optional, some are mandatory.
In case you select a combination that is not valid or you do not use a mandatory option the usage/help will be shown.
This erorr message ( EADDRINUSE ) means that the service is already started and running in the background. To be more precise the port ( 9001 ) on this server is already in use. This could either mean that “a” service or frontail already is runing on port 9001.
I see two options here:
a) stop the service first with command
sudo systemctl stop fronttail.service
and then do your trial on the command line.
b) edit the configuration file ( /etc/systemd/system/frontail.service ) that starts the service automatically at system start
once the file is configured restart the service
sudo systemctl restart frontail.service
I suggest that you have a look into the existing service configuration file.
Check for the row that contains ExecStart and extract the options that are used there.
Go with options a) and do a few trials on the command line.
Once your are happy with the result and the command line is working edit the configuration file.
Keep a copy of the configuration file. In case the service does not come up again after modification you easily can switch back.