You can insert rows and columns anywhere within a table. Simply click in a cell that is immediately above or below where you want to add a row. Or, click in a cell to the right or left of where you want to add a column. Then, choose Table > Insert > Row or Table > Insert > Column.

To select rows or columns to delete, drag the arrow pointer over a table edge and then Shift+click the arrow pointer, or use the commands in the Select submenu of the Table menu (such as Odd Rows). Then, choose Table > Delete > Row or Table > Delete > Column.