Karen, you are not dumb at all.  I struggled for ages with photobucket, avatars etc.  You say that you have got as far as it saying copied on photobucket.  What I then do is go back to the forum and the message section where I want to put the picture and right click mouse and then left click paste.  This should then put the link in (I cannot usually see the picture itself unless I go into preview, but it should appear once it has been posted).  Good luck
Ann