All day on December 25, TUAW presents "Now What?" We've got first steps and recommendations for all the Apple gifts you (hopefully!) found under the tree today. Happy holidays! If you're a Mac veteran, send a link to this post to the switcher on your holiday list.

Merry Christmas, new Mac owner. First of all, congratulations! Welcome to the family. There's some eggnog on the table, and feel free to put your coat on the bed. Setting up your new Mac is a famously easy experience. It should take about 10 minutes, depending on the kind of Mac you bought, and where you want to put it.

Once you have your new Mac on your desk, it will take you through a short setup process to personalize your new machine. You'll choose a username, a password, and will be given the option to register your Mac and sign up for MobileMe, if you want. (You can register and sign up for MobileMe later, if you don't do it now.)

If you bought any applications along with your Mac (like Microsoft Office, for example), you can install them very easily. Just insert the disc, and either drag the application to your Applications folder (on your hard disk) or double-click the installer application. You can eject the disc when you're done by dragging it to the Trash, or pressing the eject key on your keyboard.

For Windows compatibility, get your Windows XP (SP2 or SP3) or Windows Vista disc ready, and double click the Boot Camp Assistant in the Utilities folder (it's inside your Applications folder). Boot Camp Assistant will walk you through the process of installing Windows on your Mac. It's not difficult, but it will take a little time. Once Windows is installed, you can hold down the Option key before your computer boots to choose which operating system to run, or select a permanent preference via the Startup Disk pane of System Preferences. You can read more switcher-specific tips in our Switchers category.

If you're switching to the Mac platform from the PC, I might humbly suggest you read Part 1 and Part 2 of my experience introducing my dad to the Mac. He was a hard-core PC user until he fell in love with his Mac mini.

Continue reading for a few best bets about how to extend and protect your new Mac.