Steps

1. Choose Software Update from the Apple Menu.  You see that a check for new software similar to the following begin:
   
   
   
   
   
   
   A list will be created that shows the updates that are available
   
   
   
   
   
   
   
2. Select the items you want to install (uncheck the items you don't want to install)
   
   The example above and the one below show how Software Update displays information about a particular update.  Just click on an item to view its description.  Also note the left pointing arrow for updates that that will require your Mac to restart.
   
   
   
   
   
   
   
3. Click Install
   
   
4. Enter you Mac Admin user name and password
   
   
   
   
   
   
   
5. You'll see a progress of the install occur one by one similar to the following:
   
   
   
   
   
   
   
6. After the update is complete, you may need to restart depending on what was installed.