Doing logistic regression using epi-info

Hi there!
I'd really appreciate help with this one.
I'm finding the prevalence of anemia and its determinants.
There are about 23 factors that many be associated with anemia and they may or may not interact.
I need to find the prevalence in various groups,the prevalence before and after correction for trimester of pregnancy,altitude and smoking.
I also need to know which factors are associated with anemia keeping in mind that multiple factors may operate in each individual and augment each other.
I want to know how to perform logistic regression using epi-info.