If you are accessing this site, downloading TuneECU should be just as straightforward. Click on this link: Windows Free Version of TuneECU
You must have a computer or laptop or notebook running Windows -- the Android version will not work on the Rocket, and there is no option for MAC or iOS devices.
Some of our captains (including this one) keep an old laptop around just for this purpose.
If this doesn't work for you, you need to find a friend or other help with a computer. Otherwise, if you ride your bike to northern Virginia, you could stop by my place and we could check it out.