Ok, once in the Free Agent section, you can click on the
[ Claim ] link. If your roster is already full, then you will be prompted to add a check mark next to an existing player on your roster that you would like to drop in order to add the Free Agent to your team.
I just did this and now it says that it is pending, and I have a "Waiver Claim". Once I figure out what this is I'll let everyone know
EDIT: Yikes!
I just got a notice that my pending trade will "process at approximately Sep 13, 3:00 AM ET.". Ok, that is after the weekend, so if my lone DB doesn't play this weekend, then I'll be out a bunch of points