Don't worry Carol. I made the same mistake the first time I used the cross post function.
The general consensus seems to be that it is acceptable to use it to share other peoples work to a community. But seriously don't worry about the double post or giving back anything to anyone.
EDIT: I just checked your blog and you haven't reproduced the post, I promise! It is posted perfectly to both The Ink Well and your blog (but as one instance of the post) as I can see it in both locations. If I was a steem high school teacher you'd get an A* ;-)
Everyone on steem understands that there is a learning period with all of these new features with communities. Also, I think that as soon as the developers get back to work, they will be looking to simplify things.
It is a case of being patient. Also, I think you're doing fine for someone who is 'self confessed' technophobe ;-)