To be able to create or modify PE 4 or 5 images, install Bootable Media Builder on a machine where Windows Assessment and Deployment Kit (ADK) is installed. If you do not have a machine with ADK, prepare it as follows.
To prepare a machine with ADK
Assessment and Deployment Kit (ADK) for Windows 8 (PE 4.0): http://www.microsoft.com/en-us/download/details.aspx?id=30652.
Assessment and Deployment Kit (ADK) for Windows 8.1 (PE 5.0): http://www.microsoft.com/en-US/download/details.aspx?id=39982.
You can find system requirements for installation by following the above links.