Don’t apologise – no-one downloaded WP and knew what to do instantly. I’m still learning too.
Depending on what template you’re using, that’s the one you need to edit.
First, check which templates you’re using:
In WP, goto Presentation. On that page it’ll say “Current Theme” (that’s the one we want to edit)
In Dreamweaver, find the folder that holds those particular template files. It should look like this:
wp-content > themes > (your template folder)
The two default themes for WP are Classic and Default.
You’ll probably only want to edit the Main Index template, as it sounds like you just want to edit the front page of your website.
Since you’re editing your original template files, make sure you back them up first (just copy the directory and save it I guess), just in case you accidentally make changes that you didn’t intend.