First caution, of course, Save Project File AS routinely, giving it a unique # or name, so as not to overwrite prior saves. Using Save Project Files (no AS) will overwrite. From the HOME tab, that choice is available by clicking the chevron to the right of the Save Project button on the toolbar. That's protection for your project.
Saving a portable project is good too.
It's wise to clear the cache prior to working on a new project or reloading one after another has been worked on, A clean start, though load time will increase to build the cache.
But if you're resuming a single project, and no other has been loaded in the interim, then don't clear the cache between sessions.
Videopad is non-destructive; it won't affect source files. Don't move them until you are certain that the project is complete.