If you recently picked up a new Mac, iPhone, iPod or iPad, you may have seen mention of something called iCloud when setting up your device. If you don’t already know, this is a free syncing and backup service from Apple that aims to keep all your tech – mobile devices running iOS 5 or later, and desktop computers running OS X Lion or later, or Windows Vista or later – on the same page, with the same data, no matter which one you’re using at any given moment.

iCloud does a lot of amazing things: it keeps your mail, contacts, calendars, reminders and notes in sync among your various computers and iOS devices. It instantly copies that photo you took of your cousin on your iPhone to your Mac, iPad mini and laptop. It lets you work with your Macs from afar, helps you find stranded and wayward devices, and lets you know when your friends are nearby. And it does it all for free.

But what if you’re unsure how to set up iCloud or how to get it to work on your Mac, PC, iOS device and Apple TV? Here’s how.

Sign up for an iCloud account

A few notes before we begin: although signing up for iCloud is free, you can’t do so just anywhere. You must create an account on either a mobile device running iOS 5 or later, or a Mac running OS X 10.7.5 or later. Unfortunately, Windows users will have to create an account on one of these platforms before they can log in from a PC.

Apple also limits you to 10 iCloud accounts per device. You should only ever need one or two, so you’ll probably never run up against the limit; but because the limit persists after full device wipes, you may see a warning about this if you’ve received an older iOS device or Mac. If you do get an alert preventing you from creating a new iCloud account, we suggest going to your nearest Apple Store, where they should be able to help you sort it out.

Do you have an Apple ID?

If you’ve ever purchased anything from the iTunes Store, App Store or iBookstore, you’ll have an Apple ID. (It’s probably the email address you used when signing up for iTunes.) When you log into the iTunes or App Store with this Apple ID, you’ll see the email address already filled out in the Apple ID section of the iCloud screen.

All iCloud accounts stem from Apple IDs, so are easy to create. You’ll still be able to use your Apple ID for everything you currently use it for, but you’ll also get all of iCloud’s features. And if you have family members who use your Apple ID, they’ll still be able to use it for purchases without getting all your iCloud information. (For more information on managing multiple Apple IDs and iCloud, see our explanation about common signup scenarios at bit.ly/12anzdo.)

To convert your Apple ID into an iCloud account, open the iCloud preference screen on your iOS device or Mac, and then sign into iCloud with your current Apple ID and password. The screen will prompt you to agree to iCloud’s terms and conditions; once you do, you’re ready to begin.

Note: If you do convert an Apple ID into an iCloud account, you won’t get an iCloud email address (@icloud.com) by default. If you want one, simply go to Settings > iCloud on an iOS device and toggle the Mail switch on (or, on a Mac, click the tickbox). You’ll then see a prompt to create an iCloud email address to go along with your account.

Starting from scratch

Never used iTunes before? On an iOS device, go ahead and tap the Get a Free Apple ID button at the bottom of the iCloud settings screen. (On a Mac, click Create an Apple ID.) 

The screens will request your birth date and name, and ask whether you’d like to use a current email address or create an iCloud.com address for your Apple ID. Even if you elect to use your old email, you can create a new iCloud.com address after making your account by going to Settings > iCloud and turning on the Mail switch.

From there, you’ll either have to enter your current email address or type what you’d like your new iCloud email address to be. The service will also prompt you for a password for your account and a security question.

After that, to finish up, simply indicate whether you want to get email updates from Apple, and agree to the terms and conditions. You’re then ready to start using iCloud.

Set up an iOS device

On iOS, you have access to almost all iCloud features

Originally, iCloud was introduced as a sync mechanism for iOS devices, and consequently the iCloud signup process is easiest on your iPhone, iPad or iPod. You’ll need to be running iOS 5 or later; if your iPhone or iPod is still running iOS 4, you can’t get in on the iCloud action until you upgrade.

When you first set up your device, you should have seen a screen asking you to sign in, or sign up for an Apple ID and iCloud; even if you chose not to set that up when you first unboxed the gadget, getting an account is simple. On your device, open the Settings app and tap the iCloud entry. You’ll see a space for logging in with an Apple ID and password, and a Get a Free Apple ID button at the bottom.

Once you’ve set up iCloud on your iOS device, most of it starts working automatically. It will sync your email (if you’ve set that up), along with any previously created contacts, calendars, reminders, notes, Passbook passes (iPhone-only), and Safari bookmarks, to its central online server. Photo Stream will also automatically upload the last 1,000 photos you’ve taken. All its options are on by default; if you don’t want to sync a specific item type, tap the appropriate toggle to turn it off.

You can also start creating backups of your iOS devices by going to Settings > iCloud > Storage and Backup > Back Up Now.

Set up a Mac

The Mac setup process is similar to that of an iPad, iPhone or iPod. You use the iCloud settings pane in System Preferences. To add or create an iCloud account, your computer needs to be running OS X 10.7.5; any earlier, and you won’t have that pane. (Thomas Brand’s Egg Freckles blog has a few suggestions for using parts of iCloud on older systems – eggfreckles.net.)

As on an iOS device, once you’ve set up iCloud on your Mac, it will sync your email (if you’ve set that up), contacts, calendars, and so on. All options are on by default, except for ‘Back to My Mac’, which you must turn on manually. Again, if you don’t want iCloud to sync specific data, just click the respective toggle to turn it off.

Unlike with iOS devices, you can’t create iCloud backups of your Mac – in part because they would eat up all your iCloud storage space, given the size of most Mac hard drives. But your Mac does offer support for iCloud’s data sync, allowing compatible programs to store their documents and data there.

Don’t want to enable certain iCloud features? Just untick those boxes

Set up an Apple TV

Although your Apple TV doesn’t have access to iCloud’s calendars, reminders, notes or mail, you can still use iCloud features such as Photo Stream and iTunes Match when you log in with the Apple ID tied to your iCloud account. To do so, go to the Settings screen of your Apple TV, click iTunes Store, and enter your account information.