PageLines Customize isn't a tool, but a resource. As a result, you won't find settings for it in the Dashboard or in PageLines settings.
It comprises several files. Two are important - functions.php and style.css.
These are intended to be edited to add customized functions and style (respectively) to the site.
To access these files, you go to Dashboard > Plugins > Editor. Once there, select PageLines Customize from the drop list on the top-right, then click the Select button. In the grey column on the right, you will see pagelines-customize/functions.php or pagelines-customize/style.css. An additional file, pagelines-customize/base.php will also be seen (please don't change/edit this file, as it makes the PageLines Customize plugin work).
Functions.php and style.css are only intended for specific purposes. If, for example, you wanted to add a hook to your site, you'd use functions.php. If you wanted a unique styling added, you can use the style.css.
I hope this clarifies their purpose, use and access. If you have additional questions, this may help:
or, feel free to ask additional questions here in the forum.