If you lose your data and need to restore on CrashPlan, it's easy to do so from the application.
From the home screen first click "Get Files" for the device you wish to restore files for. You can restore from any one of your devices you have on your account.
From here you can now go through your device's file hierarchy to select what files to restore. You can select entire folders, or click the folders themselves to select specific files inside a folder. If you need to go back a folder, click the relevant part of the file path above (for example, you can click "Users" to go back to that folder which is highlighted and underlined below). Once you've selected what you need to restore, click "Get Files..." at the bottom-right.
A window should now pop up specifying what folder on your device you want your files to be restored to, if you want to overwrite files of the same name if they're in that folder already, and what you need the permissions to be. Once you've selected the options you need, click "Go" to begin the restore.
Now your restore's progress should show from the application's Download list. Once the restore has finished, you can hover your mouse over the restore to show the folder the files have been restored to as shown below.