I cannot browse the tables because our system is so large it times
out. Also, it does not let me type anything into the query field;
therefore, how does it know the table does not exist? Is there another
step in this step to show the table?
The query that is used to display the tables in the UI takes a long time to complete, which may exceed the timeout of the browser.
We have recognized this as a known issue on our end which is currently scheduled for resolution in a future release. You have a few workaround options:
1) Click "Browse Tables" and wait for a while until the next screen appears
2) Create a user in the database which has access to only the tables that you need. This will minimize the query time allowing you to browse only the necessary tables
3) Create a view within the database that has your header/detail relationship and create a Database Schema (not advanced) with this view.