ports in general

need somebody that knows some general knowledge of making ports square that is

just looking out for the correct way to figure out how to make a port in any box any way any sub. explain as if i where a 2 yr old. thanks

You should begin by studying several subwoofer manuals, looking at the vented box and port dimensions.  Most manufacturers provide detailed data on port size and picture how it should look.  Here is one example:  http://www.kicker.com/06/tech-support/manuals/manuals/2006/2006%20L7%20Sub%20b01%20WEB.pdf

Here is a list of audio manufacturers:  http://www.ht-audio.com/audio.htm#Driver%20Manufacturers and you can also find PDF manuals online through many of the web retailers' sites;  Crutchfield, for example.