Data validation example

Hi again,

Here’s what it sounds like a good data validation example. I attach photos with the article.

There’s no source code and I’d like help in interpreting what goes in some of the sections to be able to complete the suggested code.

For the purposes of my form I want to validate:
required fields -including a select.
valid email regular expression.
valid health number with regular expression.
red inline error messages.
hints in fact I’m not going to use.
And, I can’t use global variables.
Just Javascript no JQuery in this case.

Here is a link to my form if necessary here:

None of the sitepoint books deal in depth with forms. Just one or two very short examples just checking 1 or 2 things in not a real life form. And I think this would be a very useful reference.