Did you get them up on Photobucket? Tell us your progress so far and we may be able to give more detailed instructions.
It's like learning to ride a bike or water ski; once you've done it you'll wonder why it took so long.
To put them up on Photobucket follow the instructions there. It's pretty much a matter of "browse" and "click".
To paste them here I open Photobucket in a SEPARATE browser from BoaterEd (you don't have to but it's easier for me). I find the pic I want; and there are 3 blocks below it. Click on the words "IMG code". It's copied automatically. Then move the cursor over to the quick reply window in Boater Ed and "paste" it in. Then go back to the Photobucket window and get the next one. Once you have them all put in your text if you haven't already. Preview, edit as required, and submit.