This is what you need to do:
1. Go to the registry and take the knowledge test. Study
this handbook before you do. I assume you've already done this though.
2. You have to get your motorcycle insured. According the registry that I just called, you should be able to get insurance if you've successfully completed the knowledge test.
3. Once you've got your proof of insurance, you can bring that along with your license/learner's permit and get your bike registered.
You should be all set then but can only ride with someone else who has a full class 6 (motorcycle) license.
Another option is to do the weekend riding course to get your license. I have a list set up
here. They provide you with motorcycle, helmet, and insurance for the bike. All you need is to have successfully passed your knowledge test.
Let me know what step above is causing you problems if this doesn't work.