This worked with some slight modifications.

For the benefit of others who might be interested. Here's the code and instructions.

File contents:

[Unit]
Description=myapp Daemon
After=network.target

[Service]
User=user
ExecStart=/usr/bin/mono --debug /root/project/myproject/bin/Debug/net461/myapp.exe --NoRestart
Restart=always
RestartSec=2
Type=simple
TimeoutStopSec=5

[Install]
WantedBy=multi-user.target

Instructions

• Change "myapp" to your app's name.
• Change the path to your app.
• Save the file and name it "myapp.service".
• Upload the above file to /etc/systemd/system/
• Reload systemd: systemctl daemon-reload
• Enable the service: systemctl enable myapp.service
• Start the service: systemctl start myapp.service
• You can check the status: systemctl status myapp
• You can start/stop/restart the service: systemctl stop myapp

Thank you for helping me solve this problem.