What is a one-sentence summary of the following article?
Click on the iTunes icon on your dock. If you cannot find it, select Go from your Finder menu, click Applications (⇧ Shift+⌘ Command+A), scroll to iTunes and double-click it. From the iTunes menu bar, click iTunes, then Check for Updates. iTunes will now start checking online for updates. If there is an update available, iTunes will ask if you want to download the new version. Click Download iTunes to update to the latest version of iTunes.

Summary:
Open iTunes. Check for updates. Download the iTunes update.