Make sure to follow the instructions to install from binary before.
Run the below command in a terminal:
sudo vim /etc/systemd/system/ftpgrab.service
Copy the sample ftpgrab.service.
Change the user, group and other required startup values following your needs.
Enable and start FTPGrab at boot:
sudo systemctl enable ftpgrab sudo systemctl start ftpgrab
To view logs:
journalctl -fu ftpgrab.service