I appreciate your patience.
Main website -- I am referring to our website.
Then we decided to create a blog. -- enter WordPress.
So I am not trying to replace our website.
so in response to your note "If so you can put wordpress in a folder call it from there and take down the html
I will not be doing this.
then you wrote "you call your wp site from index.php , if this is the case just have a look at the urls in wp admin settings."
Am I understanding correctly that this notation would not apply to my desire to have a blog website with the theme I chose.