You are now provided with a list of available updates. Each update provides the update name, the update version, and the file size. Also, if a particular update has the small arrow icon in the left frame, it signifies that a restart of your computer will be required once that update has completed installation.
When an update item is highlighted, a full description of the update is usually provided in the bottom frame as is the case in the screenshot below.
You will notice in this example that a Safari update is indeed available. It is usually a good practice to install all available updates for any software that you use, even if you only use a certain software package sparingly. Also, you should always install updates with the word security in the title.
To select or deselect items that you would like to install, use the checkboxes directly to the left of their respective names. Note that some items will always be checked by default, including operating system security updates.
