Drilling down means to go a level deeper in detail. You can drill down into a composite block to see the components of the composite block.
In the Hierarchy View, select a composite block.
Right-click the composite block, and then click Drill Down (or double-click the block to which you want to navigate in the diagram.). The components and parameters for the block are displayed.
Tip
You can go back a level by right-clicking, and then clicking Back Out.