Chrome is a web broswer that is created by Google. It is optimized and the preferred browser to use for Google Apps.
This document describes how to sign in to chrome
The chrome user documentation is located here
This document describes how to clear browser cache on several different browsers.
This document has some guidance to help resolve sync issues.
If you see a message box like the one below and have recently changed your password you will need to provide your old password to get sync back working again.