There's a little eyedropper thing in that popup when you click the uBlock button. Use that to select elements you want to block. Sometimes what you click is a

There's a little eyedropper thing in that popup when you click the uBlock button. Use that to select elements you want to block. Sometimes what you click is a few levels deep in a container. After you select one, you can click through the items in the "Cosmetic Filters" box until you get to the right level to block the entire element.