iep-printing is the customization plugin for PowerSchool that works with iep-printing-php to bring printing of PDFs to Form Builder forms.
iep-printing is installed like any other customization plugin to PowerSchool. Download archive.zip from the releases page and upload it on the PowerSchool customization plugin management page.
Open iep.js and change the api url at the top to point to where you installed iep-printing-php.
Open the other two javascript files and edit the URLs toward the top of the page to point to where iep.js (if you installed this with the zip, this means removing the domain portion e.g. https://ourdomainname.org otherwise, change the domain name to your PowerSchool image server's domain name).