New account can't send to recipient list

We just signed on, we are in the free trial. We created a mailing list with a little over 1500 email addresses. Is there any particular reason why we can't run a campaign?  When we go to schedule it to run, the box is greyed out and we can't select our list. I'd just as well skip the free trial and get the $40 subscription if it means you'll unlock this program and allow us to use it. I mean, what good is a trial if we can't trial it?  Does it work or not?