Running the Telos services using systemd rather than a simple start/stop script gives you some neat advantages. Systemd can auto start those services at boot time, restart them automatically when they fail and uses a binary logging system that is very powerful when it comes to filtering, storing and rotating the logs.
Copy the service files to /etc/systemd/system. You probably need to adapt some paths for your Telos data/config directories. If you did not execute make install after building Telos you also need to adapt the executable path (make sure you always use the full path, even if the nodeos executable is in your PATH environment variable).
The Telos services are run as telos user (do not use root to run your nodes), this means there either has to be a telos user on your system or you need to adapt the user/group setting as well.
To start a service such as the Telos node, simply run systemctl start telos-nodeos.service or systemctl stop telos-nodeos.service to stop it. You can find the current state by executing systemctl status telos-nodeos.service.
To automatically start a service after the system has booted up, use systemctl enable telos-nodeos.service.
You can use journalctl to view the log files, by calling journalctl -u telos-nodeos.service. Useful options are -f (continously prints the newest log entries to the console), -e (jumps to the end of the logs), --since (shows entries that are newer than the given date) and -b (shows the log entries since the last boot). All options can be found in the official documentation.