Beginner problems

I have a few problems:
1. titles/headers in collections and exhibits appear twice, in two different sizes. How can I have only one?
2. "Dublin Core" appears on public pages. Is this supposed to be there? If not, how can I delete this?
3. Under "items" text and photograph or image do not appear. Instead, titles of previous items are there. How can I revert to the original drop down list?

Thank you

1. Can you take a screenshot or share a url so I can see the problem?

2. If you go to the Appearance tab on the top nav, and click from there to settings (so admin/appearance/edit-settings ), there's a checkbox for "show element set headings." If you uncheck that box, it will not display Dublin Core.

3. Under which "items"? Items browse? When viewing a single item?