How do you submit a NOTAM?

Hello,

New to aviation and I would like to know how to submit a NOTAM. I plan
to launch an unmanned free balloon a few months from now with a
payload of scientific instruments weighing less than 4lbs. The
projected flight-path will take the balloon only through CLASS G and A
airspace (and maybe Class E). According the FAA, an unmanned free-
balloon with a payload less than 4 lbs does not require prior
notification before launch. However, I think it would be prudent to
submit a NOTAM.

I would love to hear anyone's experience on on unmanned free-balloons
- should I really not worry about the NOTAM? Either way, I would like
to know more about submitting them.

Thanks,
John