I made some mistakes when I set the original para styles and they have become some sort of default that has to be corrected for every new project. Do I have to delete the whole thing and start over again? I can do it, but I hope I can do it an easier way.

Resetting your paragraph defaults is very easy. To do it globally (for InDesign as a whole), close all your documents. Go to your Paragraph Styles panel. Delete all styles listed. Delete all the character styles in your Character Styles panel also. Choose Load All Text Styles… from either panel menu (it’s the button in the upper right corner of panel ). Navigate to the document which has the styles you wish to use for your default. Choose it and click OK. That will load all the paragraph and character styles into your two styles panels. They will now be the default for every new document you open.

You can do the same with Object styles.

To add these styles to an existing document. Open the new document. Have nothing selected and no active insertion  point. Do not delete the currently used styles (or all of your paragraphs will become unstyled). Then load those same styles (from the same source) into your document. This process is not quite as clean. It will overwrite any styles with the same name, but it will not delete styles with a different name. For example, I commonly get something like 7-Sub 1 in addition to the list which contains 7-Sub. In this example, I simply right-click on 7-Sub 1 and choose Delete Style. This gives me a dialog box where I can choose the style which I want to use (7-Sub) in a popup list of all styles. When I click OK all paragraphs formatted with 7-Sub 1 become styled with 7-Sub and the 7-Sub 1 style is deleted.