In Windows each installer is saved to the programs folder. On the Mac you might use the finder to locate the VP executable. If that fails 6.03 may be available here.
That's not a sanctioned NCH site, but appears to be legit. Beware of extra offers during the install, and reject them.
Unfamiliar with Mac user interface nuances here, but the process of saving as a portable project should be similar to Windows versions. Here's what the general HELP file says...
Finalize a Project - Backing Up or Moving a Project to Another Computer
A project file only stores the paths of media files (including video, audio, and image files), not the entire file contents. When a project file is loaded, it attempts to find and load the media files using those file paths. If a media file has been moved or deleted, or the project file alone has been copied or moved to another computer, VideoPad will not be able to find the original media files. To back up a project and all its media files, or to move a project and all its media files to another computer, select File -> Back Up Project Files to Folder, or Save Portable Project As. This will save a new copy of the project (.vpj) file in the selected folder, and all media files used in the project will also be copied into the same folder. This entire folder can then be saved to backup media, or copied or moved to another computer.
Once the portable project is saved, follow the instructions in the link above to upload and share it here or in a private message.