You can make changes either using your normal edit interface or through the shell access.
The easiest way to make changes is usually through whatever interface you normally use, for example by going through cPanel > File Manager and opening the file with your server's code editor, however using a editor like PhpStorm will save immeasurable amounts of time if moderate changes are made. You may also want to familiarize yourself with Tiki's DevTips and Secure Coding Practice Guidelines. After you've made and saved your changes, go to Step 4.
Expand the instructions below if you're making changes through the shell access instead.[+]