This was detailed over a year ago, but a lot changes. A refreshed look at how you can make a whole fleet of iPad devices communicate together and offer students a universal experience.
Before starting, updating the software to the latest version of iOS wouldn't hurt. Everything but an original iPad can run iOS 7.1.2 (current) and will be able to run iOS 8. When iOS 8 arrives in the fall, I won't update my devices until it's time for regular maintenance over winter break.
You may have done this already when setting up the device. It asks for an Apple ID at the start. If you're inheriting devices or weren't the one who took it out of the box, you'll want to sign in your account here. Use an e-mail address separate from any personal Apple ID you use. Every device you sign in with the account will able to access the same batch of purchases.
Disabling automatic downloads will prevent student devices from grabbing copies of things you may not be ready to deploy yet. Enabling Auto Updates will apply updates as they become available, preventing you from manually applying them on every device.
Acquire purchases by launching the App Store from the home screen and finding the "Purchased" button on the bottom right.
You shouldn't have to do anything extra. By signing in to the App Store with your Apple ID, it should appear here as well. It's also possible this was entered at set up. Again, if you're inheriting a device or did not set it up initially, you'll want to check here. Notice most of the features are disabled. The Safari features let each device share a common pool of bookmarks, it also enables one device to see what tabs are open on others. To enable the kind of fun photo discussions I've done in class, you'll want the photo feature enabled. This allows devices to contribute to a common photo pool. Photos actively in the shared pool appear by going to Photos > Albums > My Photo Stream.
You'll first need the Google Drive app from the App Store. I use Google Drive to accomplish another type of classwork sharing. Every device is signed in to an account I made specifically for this purpose. If your school e-mail is tied to a large scale Google Apps for Education deployment like mine is, you won't want to use that. In theory you can ask students to sign in to their own Google Accounts here if they have them, but this is less fiddly.
Students will distract themselves no matter what, but a few options in the restrictions screen will prevent them from doing any real damage (like deleting an app). When you first tap Enable Restrictions you'll be ask to set a passcode. This is different from a passcode to unlock the device. After restrictions are enabled, you will need this passcode to make changes.
I disable a lot of features. All of the iTunes and App Store related ones will remove the icon from the home screen. If you enabled Auto Updates as mentioned previously, they will run with the App Store hidden. If you choose not to do Auto Updates, you'll need to come back to the restrictions screen and flip the switch any time you want to check for updates. Without the icon present, you'll never know they exist.
Towards the bottom of the Restrictions screen are options for Twitter, Facebook, and Accounts. In each case you'll want to disable the ability to make changes. Since you can't delete the Mail app or Messages app, you'll want them to be nonfunctional if a student attempts to open them. When properly set, Mail and Messages will display the error above. Hitting OK drops back to the Home Screen.
No need for computer based syncing, no need for backups, and no need for any crazy apps. My devices are designed to be clones of one another that allow any work created to be offloaded quickly.
More importantly, with iCloud and Google Drive, students get a chance to talk about what others are creating. iPads shouldn't be expensive workbooks.