Go to a photo hosting web site like photobucket (just add .com at the end).
Open an account (it’s free).
Upload photos from your computer using the browse button.
After you upload the picture there will be several boxes below the picture, click on the one that has before and after the link, when you click on it, it will say ‘copied’
Then return to this site, open a new post reply, and place the flashing cursor in the body of the post, ‘right click’ and select ‘paste’. Then type your message and your picture should appear in your post.
You never said what parts you were missing….
Good luck, David