I am not sure I undertand you question, Julie. Basic Creo Parametric does not have view ports. It simply has a graphics window (unless you have the style option).
When starting a new part, the default datums planes can be huge. Once a feature is created, these scale to the extent of the bounding box, which is the size constrained by the newly created physical geometry.
Feel free to show some images or even a video of the problem you are having.
