Simple Rowspan example :
Row 1 - One long cell Row 2 - Cell A Row 2 - Cell B
Simple combination of the 2 :
Column 1 Column 2 - Cell A Column 2 - Cell B
Little more complex example :
Column 1 Column 2 / Row 1 - Cell A Column 2 / Row 2 - Cell A Column 2 / Row 2 - Cell B
Top Row Column 1 Column 2 / Row 1 - Single Cell Column 2a Column 2b / Row 1 Column 2b / Row 2 Column 2b / Row 1 Column 2 / Row 3 - Single Cell