If this is a new diamond saber and your first time with a diamond board, read on... otherwise what I'm going to say is moot.
you might not have a data-cable, but a charge-only cable... so if you have any other USB cables available, try that... usually electronics come with a cheaper cable that doesn't have the data side to it... ones that do will be those that expect you to connect your item to a PC (for instance, I use my Kindle cable)
the sequence is tricky once you have ascertained you have a data-capable cable: plug in the cable to your diamond board, turn on the saber, plug the USB side to your PC.... wait for it.... wait for it... wait for it... eventually a little pop up or default ding happens and your PC knows what to do with this. Now, open the UltrasaberLauncher.
Once in the launcher, you should not have to fiddle with any of the 'auto' stuff... but you -will- want to update firmware. My dominicide repair came back with a very old firmware on the diamond board that prevented the hold-stab motion to change font... freaked me out thinking I had a bad diamond. So, that's the first step.
Next, with a diamond board, you want to switch to the "Diamond" tab... sometimes, that's not obvious. You should see a listing of your fonts with your custom one being the first, then the standard default set. You should click on that first one (blackstar, iirc) and go to Advanced mode, then save that font package to your PC... this is the only comes-with font that you won't be able to recover (the rest are default and available publically)
Good luck!