Select an asset in the Browse Panel so you can work with it. Use these techniques to select assets:
A single asset - Select the asset (double-clicking opens the asset in Detail View).
Several assets - Ctrl+click (Windows®) or Command+click (Macintosh) assets to select assets in different places on the Browse Panel. Shift+click (click one asset, and then Shift+click another) to select adjacent assets.
All assets in the Browse Panel - Go to Select > All.
No assets - Go to Select > None.