align - Sets the justification of the cell contents (see above for possible inputs)
valign - Sets the vertical justification of the cell content (see above for possible inputs)
colspan - Tables are meant to be grids, but this makes it so you can join cells horizontally
rowspan - Distance of the cell walls from its contents
* = mandatory
This is probably pretty confusing right now, be sure to read all our HTML table tutorials and check out the examples so you can put together all you have learned.