Personalizing the "first name" field with ELMO

Hi. I am new to Eloqua, and new to setting up ELMO templates for my sales users. I'm sure this is a simple question, but I've searched and can't find the answer. I am creating templates for sales where I want to personalize the "first name" field, i.e. Dear <<firstname>> (i'm using E9). When in the template, I inserted that field, but when i did a test send, no name populated. I'm sure I'm missing a key step, but i'm not sure what it is.

Thanks,

Angela