How do I create custom attributes?

[bayshorecreations]

I am looking to make a dropdown option where people can choose the size of an item they would like to purchase.
For instance,
4'x10' = +$20
5'x12' = +$30
6'x14' = +$40

and so on.
I am a total newbie to zen cart if you cant tell...lol
Thanks for the help!

[bayshorecreations]

Ignore this post please. I figure it out.
Thanks

[Ajeh]

Thanks for the update that you found where to make the Option Names, Option Values and Attributes for your products ...