The cell layout for each table is defined in the corresponding style TableN which is automatically created when you add a table to your document. These are the default table settings, which you will probably want to alter:
You should make any changes which you want to apply to the whole table by altering the settings in the ruler when no area of the table is selected.
The type style, border, colours and the grid are altered using the style dialogue box by editing the appropriate table style or creating new styles and applying them to the table.