You can use the Contact Library Staff box in the left column of the page, under the navigation tabs.
The final step will be to make the Discovery Search a Floating box:
You should now see a recycle icon and a life preserver ring icon, after the box title. This indicates that you have mapped to a box from another guide and you are hiding the box title and borders.
Scroll to the top of your guide and click the to preview the page and double check that the box looks as it should.