There are two ways to install updates on a Mac and both are outlined in this article.
Using the Mac App Store
1. Click the App Store app on your Mac.
2. Click Updates in the toolbar.
3. Update each app individually or click Update All to install all available updates.
Using Software Update
1. Click Software Update from the Apple menu.
2. Follow the onscreen instructions.
NOTE: Some software updates are also available from the Apple Support Downloads site.