New Post: Cascade Dropdown SharePoint 2013

Hello,

I am trying to implement cascading drop downs in SharePoint 2013 hosted on Office 365. I am not sure how to include the script to call SPServices on the New/Edit forms. It appears that edits are disabled in SP Designer. I have tried to include them using Script Editor WebPart. This results in a blank form. Any help would be greatly appreciated.

Thanks!