Setting up SSL on Lighttpd
Setting up SSL on Lighttpd is very easy, however there is one thing you should note: When setting up a secure webserver, you must be careful that the website associated hosted on your secure server uses the HTTPS protocol in your code. Chrome, Firefox, and Edge all have an icon to the left of the URL that have navigated to. This icon will appear as a lock when the page is secure. If you have images or links that load from a non-secure link, it won't matter if the server has SSL enabled, the page will appear as if it is not secured. This is important to note when upgrading your server to SSL. Not only does the server configuration change, but your website's code will also need to be updated in order to maintain security.
As far as a guide goes for setting up SSL on Lighttpd, there are many sources available with a simple Google search. I leave it to the reader to figure this out. Some guides are more vague than others, so you may require sourcing this information from multiple locations. Also, I highly recommend the "Let's Encrypt" certificate generator, as it will allow you to generate trusted certificates for free. You can find more information on Certbot at their website: Certbot.eff.org.