The SetVarValueExtra Command sets the value of a variable to one of the options available. There are currently only two options available in Database Control Pro. The extra options require some server 'effort' to be worked out, this is why they are not default variables.
The Command name can be anything you like, it makes no difference when the sequence is run and is purely for organisation purposes.
The 'Command Type:' line reminds you of the Command Type as you might choose not to put it in the Command's name.
The remaining properties are specific to this Command Type.
Variable Name - The name of the variable to set the value of.
Variable Value - The new value of the variable. It has to be one of the options available, currently 'Num of Rows' and 'Num of Cols' are the only options where the number of rows or columns in the database are retrieved (by counting the rows from cell 0,0 to the cell with the highest row/column number).