In Puppy Linux the software that can be installed in a computer comes bundled in files with the pet extension. Pet packages are nothing more that directories containing programs in an archived format. So, if you want to create a .pet package you have to have a directory containing the subdirectories and programs that you need. That being said, to create a .pet package:
If the application that you want to package has a menu entry you have to add an icon and write its path in /usr/share/applications/your_application.desktop. In here you have also to add the path to your executable file. Images can be stored in in /usr/share/pixmaps, but you can choose other places. Just follow the instructions that appear in the terminal.