Once you have entered the macro, running it is as easy as :

1. ALT-F8
2. select the macro
3. touch run

Macros can have arguments, but that's mostly for macros called by other
macros or event macros.  Usually macros pickup information from worksheet
cells and user input.

For example, you originally tried a function and wanted a result in a cell
and its adjacent neighbor.  In using a sub you could just select that cell in
the worksheet and run the macro.

To put a value in the selected cell:

ActiveCell.Value=whatever

to put a value in the adjacent cell:

ActiveCell.Offset(0,1).Value=whichever

start out by reading:
http://www.mvps.org/dmcritchie/excel/getstarted.htm

or

http://www.lqnet.com/Excel/Excel.asp?gclid=CKaVwuCGkIcCFSydFQodi1EBpg