Definiation:

Upstart is an event-based replacement for the /sbin/init daemon which handles starting of tasks and services during boot, stopping them during shutdown and supervising them while the system is running.

Upstart Processes reside in /etc/init/

Go to process directory

cd /etc/init/

Create Conf file

Create your process config file in there
e.g process_name.conf using your preferred editor.
vim process_name.conf

example of Upstart config file:

description "Job that runs the foo daemon"

# start in normal runlevels when disks are mounted and networking is available
start on runlevel [2345]

# stop on shutdown/halt, single-user mode and reboot
stop on runlevel [016]

env statedir=/var/cache/foo

# create a directory needed by the daemon
pre-start exec mkdir -p "$statedir"

exec /usr/bin/foo-daemon --arg1 "hello world" --statedir "$statedir"

Check Syntax

Check your process conf file for syntax errors using:
init-checkconf -d /etc/init/process_name.conf

Reload Upstart

Relaod upstart to recognise your process
initctl reload-configuration

Control your process

Control the process using:
sudo start | stop process_name

Upstart vs Systemd Commands

Operation Upstart Command Systemd equivalent Notes
Start service start $job systemctl start $unit or service $unit start
Stop service stop $job systemctl stop $unit or service $unit stop
Restart service restart $job systemctl restart $unit or service $unit restart
See status of services initctl list systemctl list or service --status-all
Check configuration is valid init-checkconf /etc/init/$job.conf systemd-analyze verify <unit_file>
Show job environment initctl list-env systemctl show-environment
Set job environment variable initctl set-env foo=bar systemctl set-environment foo=bar
Remove job environment variable initctl unset-env foo systemctl unset-environment foo
View job log cat /var/log/upstart/$job.log sudo journalctl -u $unit
tail -f job log tail -f /var/log/upstart/$job.log sudo journalctl -u $unit -f
Show relationship between services initctl2dot systemctl list-dependencies --all

More detailed explanation to the slightest differences between Upstart and Systemd can be found here:
https://wiki.ubuntu.com/SystemdForUpstartUsers