First off... Welcome Aboard!
...and kudos for jumping right into a challenge.
To attach files I always click on the "Go Advanced" button at the bottom of the entry screen. Then scroll down to 'Additional Options' and you'll see the "Manage Attachments" button. Pretty straight forward from there.
A couple of things to remember, there are file size (depending on the file type) and pixel dimension limitations (~33megapixel). Though from what I could see none of your images should be a problem.