Popup on red/green button click

Hi,

I’m loving the simplicity and elegance of Zerif lite! It allowed me to create a good looking website for my book, so thank you for creating this gem of a theme!

I’m offering a free chapter. The green button links to the pdf file.
I’m running PopUp by Supsystic for a popup with a trailer for the book, for everyone viewing the home page.

Now, i’d like the green button to open a popup where you’d have to sign up in order to get the free chapter. There is an option in the plugin for having a popup on click and it’s telling me to

Copy & paste next code – into required link to open PopUp on Click:
[supsystic-show-popup id=102]

Or, if you know HTML basics, – you can insert “onclick” attribute to any of your element from code below:

onclick=”ppsShowPopup(102); return false;”

Or you can even use it for your Menu item, just add code:

#ppsShowPopUp_102

Where and, especially, in which file can I insert this code?
I have virtually no php knowledge, but i can figure it out. In the big_title.php file i see $something often. I believe these are variables set by input in the customizing of the theme. But where are these variables stored? Where can i find (and edit) the values of said variables?

I’d be endlessly grateful if you could point me in the right direction and show me the way with some answers to my question!

All the best,
Jeroen