To add a table:
- click the
button in the lower-left of the document window
To alter an existing table:
- Select it in the source list and click the
button in the lower left of the document window - Choose "Alter…" from the menu that appears.
The table editing sheet
The upper half of the window contains the table columns and the lower half contains table constraints. Use the 
buttons in each half to insert or remove items.
To alter column constraints, click the 
icons in a row to pop up further options. From left to right these allow you to set constraint options for:
- Primary Key
- Not Null
- Unique
- Check
- Default
- Collate
- Foreign Key
The lower half of the window contains any table-level constraints to apply to the table. These can be edited in the same manner as the table columns.