If your certification has expired, you are within 120 days of your expiration date, and your continuing education and skills were completed prior to the expiration date, then you may turn in your continuing education report form and pay a $50 late fee. Follow the directions at http://www.in.gov/dhs/ems/individual-certifications/.
If it is 120 days or more since the expiration date of your certification, and you were previously certified in Indiana, you may complete "EMS - Application for Recertification Based on Previous Certification" in Acadis.
This process should be followed if you are trying to regain your certification, not if you are trying to recertify.