The cloud isn't useful only for enabling access to our photos, documents, music and more wherever we are, it also presents an increasingly viable backup medium for our data. Provided that we have access to a Wi-Fi connection, the cloud can come to our smartphone as well as our PC.

As free online storing and sharing services go, we rate Dropbox. It lets us sync files with our desktop, and ensures the latest version is accessible online, on our PC, or through a mobile app, wherever we are. But given the free account's 2GB storage limit, our head has been turned by Box.

To conicide with the release of its updated Android app (now version 1.6), which offers stronger interface features and support for Google Android 4.0 Ice Cream Sandwich, Box is offering a free upgrade to 50GB of storage from now until 23 March. Here, we explain how to use it.

Step 1. Head to Android Market and search for Box. Download, install and launch the application.

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Step 2. If you don't already have an account with Box, register for a free one now. On the Register tab, enter your email address, password and password confirmation in the relevant fields. Press Register, and Box will automatically log you into the service. If you complete this step prior to 23 March, a message will pop up onscreen advising that your account has been upgraded to 50GB of storage and sharing.

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Step 3. The simple interface displays two tabs: Files and Updates. A list of Files stored in your account are displayed on the Files tab, while Updates notifies you of any changes made since your last visit.

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Step 4. To add a file from your Google Android smartphone, click the Upload icon at the bottom of the screen. Choose to upload a photo, audio, video or other file, then browse to the content on your device. Alternatively, press the + icon at the bottom of the screen and create an image, video or audio file using your smartphone's camera or mic. Box will automatically begin uploading the file, with its progress shown in Android's notification bar. In the meantime you can continue using the app.

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Step 5. If you'll be adding several files to your Box account, it's worth keeping things organised. Click the New folder icon at the bottom of the screen, then give it a name and press Ok. You can also create sub-folders within folders.

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Step 6. Click on any item on the Files tab to access options specific to that file. For instance, we clicked on a photo and were given options to open, share, comment on (or view other people's comments), download, edit the filename or delete the file. Click the Share option to send the file via email or Bluetooth.

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Step 7. Collaborators can be invited to work on folders. Click a folder on the Files tab, then click the Share icon at the bottom of the screen. Choose Invite a collaborator, then enter their email address or choose a contact on your phone. By accessing our Box account via the company's website, we were also able to specify whether collaborators can view or edit files.

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Step 8. Any files uploaded from your smartphone are also accessible when viewing your account online on a PC, and vice versa. This means you can access your most important files on any platform, wherever you are.

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