Hover over your table and click the + New row below your bottom row. Alternatively, click into or select your bottom row, then hit Enter on your keyboard.
If you want to get fancy with it, you can also add rows with buttons!
To select a row in a Table, click the row handle that appears to the left of the row when you hover over it. Or, if you like keyboard shortcuts, click a cell and arrow all the way to the left to highlight the entire row.
Select multiple rows
Select the first row, then press Shift or Command to select another row. If you're selecting adjoining rows, you can just arrow down or up while holding down Shift if you prefer.
Delete multiple rows
Once you've selected rows, you can delete them by simply clicking Delete on your keyboard. You can also delete one or more rows by using right-click to bring up the row menu and select "Delete row".