Depending upon your location, this might be easy or difficult. The easiest way to get started with this is to look on Facebook for fire spinning groups that relate to what you are trying to do. Often times posting what you are looking for will get you in touch with a teacher.
Many communities have what are called spin jams or spin spaces that meet periodically to teach safety and provide lessons. Checking out Facebook can be a good place to find where groups meet.
There are fire spinning conferences around the country that teach classes. See the "where can I light up" section more details.
Many cities around the United States have their own Conclave groups that perform at Burning Man. Many of them accept new members at the beginning of the year. Often the groups need help with choreography, dance, costuming and management. They may be willing to trade your skills for theirs.
Many festivals teach classes. If you have a Festival in your area, contact them and see what they offer.
One of your best sources for information is YouTube. You can find hundreds of training videos for every prop can imagine.