Link should go to detail description, not topmost heading.
Update README.md to provide context and how-to information

Provide explanation of context in the README and suggestions on where to go from a blank slate of unfamiliar filenames.
Put some explanation at the beginning of the page.
Update README.md
Created the script file and changed the README.md.
Creating new .py files.
Merge pull request #176 from duncombe/push-request-2

Adding helpful information in README.md and Scenario1A Model Strings
Theme 1 - Scenario 1E - Salinity
Theme 1 - Scenario 1D - Dissolved Oxygen