The subtract Boolean produces a single solid that represents each of the stocks less each of the tools.
Pick the cylinder followed by the box. On the Structure ribbon in the Entity Modification group, click Boolean and choose from the drop-down menu. Click to close the Edit Properties dialog box.
The view now displays the result of the subtraction.
Notice that the subtraction has a presence in the Browser under the Geometry node. The cylinder is located under the Creation > Stocks node and the box is under the Creation > Tools node.