Hit the add new button on the documents and forms page and it should bring you to the new document screen.
To upload a new document hit the add file button. This will bring you here.
This is what a completed document would look like:
If you are uploading a document make sure it is a PDF for accessibility reasons.
When you add a form do not forget to add a Tag or filter group. The tag selector is located on the right side of the document screen.