It looks like you're missing a space between the source and the destination in the copy command. It should be cp files/docker-compose@.service /etc/systemd/system. The goal is to copy certain Docker files from the Central distribution to a system folder at /etc/systemd/system.
The output there actually all looks good. What you are seeing there is the result of running systemctl status docker-central@compose, but because Linux thinks the output is too long to just directly print for you it instead printed the output into a text reader application.
It's confusing the first few times this happens, I know, but it's just how it works. You can tell this has happened by all the ~s along the left margin indicating empty lines, and the highlighted lines 1-18/18 (END) at the very bottom of the screen.
Inside this text reader, you can use the arrow keys or pageup/pagedown to scroll, or you can press letter q to quit back to the main command prompt.
Don't worry, this won't quit Central; remember that the command you ran was just systemctl status, so you're just quitting the status log.