You can search the internet for .conkyrc scripts and use one you like, many of which will be configured to work on particular destops and/or require additional applications to be installed; so here is mine that I can confirm works on KDE, MATE and Gnome3 desktops. It uses minimal system resources and doesn't require any additional software to be installed, and you could use to get you started.
Thank you for this script. I like it. Now I just find that this conky is a bit too wide for my taste. How can I make it a little bit narrower and taller/longer? What changes should I make to the configuration file in this case?