Additional custom content modules?

[alchemy]

I'm currently working on a layout that requires use of two custom content modules in Tabula Rasa. I've been so used to working with LJ's S2 that it didn't occur to me while I was designing that DW would only offer one custom text module as standard in the wizard.

Does anyone know the code for adding additional custom content modules in the theme layer? Please note that I am one of those people who is very proficient in CSS but not so great at S2 or other types of coding, so step by step instructions would be a godsend.

Thanks in advance!