how does one know what to put into script to indiviualize it? is just through the documentation provided and sheer practicing skills?
That’s what the tutorial is for: it’s a detailed, step-by-step explanation of the concepts and mechanisms of the script that you can arrange to build your experimental design from scratch. Most experiments are composed of displaying some content on the page and waiting for a timeout or some interaction with the page. The tutorial explains how to display and remove text (newText/getText) and images (newImage/getImage) on the page, how to play and stop audio files (newAudio/getAudio), how to wait for a given duration (newTimer/getTimer) and how to listen to keypresses (newKey/getKey) or clicks (newSelector/getSelector). Those constitute the vast majority of the building blocks required by almost all experiments. The documentation also lists the existing element types in a dedicated section so you can learn more about how to use them, and maybe look for some that you need in a project but were not familiar with yet (eg. the DropDown element to display drop-down lists)
The How-to guides then detail how to go on about frequent, more complex aspects of designing an experiment with PCIbex
Finally, with sufficient knowledge of the script and its mechanisms, reading the code of other experiments helps you discover new ways of implementing various features, without necessarily needing any further documentation
Jeremy