Assuming it is a CF card enabled back, be sure to shoot it both firewire tethered to a computer, and to a CF card untethered.
Depending on which back it is (you failed to provide that information), download the latest version of Flexcolor from the Hasselblad site and load it on your computer. Then connect the camera/digital back to the computer with the firewire (which should be included).
If the back has old firmware and has not been updated, a dialog window will open prompting you through the steps to update the digital backs' firmware. If you are using a laptop, you will either need a firewire adapter with AC power, or have to use a fully charged battery to power the digital back (clip on type with the CFV and CF type backs, grip battery with the H camera). Most desktop towers do not need this since the firewire connected back draws power from the computer itself.
If processing through Flexcolor is initially to confusing for your first tests ... you can select all images and simply save as DNGs to a separate desktop folder and process those in any RAW program that recognizes DNGs ... like Adobe Lightroom and Adobe Camera RAW in Photoshop CS2 or 3.