@Sewing4Fun, what I hope you will understand from my response and from @Grace’s is that there are two different approaches to making a pattern work for multiple sizes.
Grace has learned and written some tutorials on how to use the multisize file (.vst). Using that approach, you create a set of “standard” sizes and use the same pattern file to generate patterns for any of those sizes.
I use a different approach, which is to use a single size (.vit) file. Using that approach, you create a pattern that works for the individual whose measurements are in the file. You can use the “Measurements” and “Load Individual” functions to regenerate the same pattern using the measurements of a different individual.
In both cases, the important thing is to construct the pattern using formulae based on the measurements. To see how that is done in both Grace’s pattern and in mine, you will need to look at some of the individual lines and curves inside the pattern and see how they were made.
If you need more help on how to do that, PLEASE ask