Hey Dale, thanks for your question!
Try re-doing the download / install a time or two.
Lots of people have reported this issue over the last several months (there was a known issue with the Google Play Store, but I can't imagine they haven't corrected the specific issue involved by now).
Double-check your network (wifi or 3G/4G connectivity), too, to make sure you've got a good, strong connection and then retry the download/install.
Cheers and best of luck!