Hi, you almost have the right idea :). Your major flaw is that the #wrap has failed to contain the floats.
Also in order to auto margin something, to horizontally center, it must have a width attached also (and it needs to be have a fix in the above link, if you have floats as children)
Try adding the code below
I don't know how the rest of your apge is going to be structured, so #wraps width will for sure need to be enlarged, but you see the general idea being workedthere :).