Right-clicking in a cell activates the table context menu, where you can edit cell, row and column properties. The following image illustrates howe to accessi the cell properties dialog.
The Cell properties dialog enables you to align the text content in the cell, as well as to set the Cell Type to either Data or Header. Here you can also set both Rowspan and Colspan dimensions
|Row 1 Column 1
|Row 1 Column 2
|right align: colspan=2