You can launch (open) an application in any of several ways:
Single-click an icon on the Launchpad, described on the following pages.
Single-click a program’s icon on the Dock, the Sidebar, or the Finder toolbar.
Use Spotlight. Hit ⌘-space bar, type the first letters of the program’s name, and then press Return.
Double-click an app’s icon in the Finder.
If you’ve added the Applications folder to your Dock, click the Dock icon to open the pop-up fan, grid, or list of icons. Then click the program you want (or even type the first few letters of its name and then press Return).
Highlight an application icon and then press ⌘-O (short for File→Open) or ⌘-down arrow.