If you're going to be working in AD, I would recommend that you download the snapin
Quest.ActiveRoles.ADManagement. It just makes it so much easier to pull information from AD with this snapin. It also comes with a complete guide on how to use the cmdlets. Just to go to Directories, Products and Services, then click on the link that'll take you to the download.
But if you decide not to do that, try doing:
$g.cn|ft samaccountname, telephonenumber, manager