The Add Tables task pane (which stays open while you work) replaces the modal Show Tables dialog box in Query Design View and the Relationships window. You can do the following:
Tabs Select one of four tabs (Tables, Links, Queries, All).
Search Use a Search box to further filter the list.
Multi-select Select multiple items:
Press and hold Shift, and then select multiple contiguous items.
Press and hold CTRL, and then select multiple noncontiguous items.
Drag items Drag selected items from the task pane to the upper section of the Query Designer or the Relationships window.