Are you trying to add your mtDNA results? Through which company did you test? To add your results, you can go to your profile, then look in the top right corner for the 'Add' link. When you hover your mouse over it, one of the choices will be 'DNA test information.' Click on that link. On the page that comes up, there will be an option to 'add a new test.' Click on the arrow to the right of 'Select DNA test' and numerous options will come up with regard to where you tested and what type of test you took. Follow the instructions and you should be good to go.
Have you uploaded your results to Gedmatch.com? If so, you would have an ID # that was assigned by Gedmatch. There's a place to enter that.
If you have any more questions, just post a comment in this thread.