(1) www.enrollri.org You would need to sign up first and then sign up for the course(s) you want to do. If you don't get into one program (during one season), you can always try another program (during another season) when it opens (Kyleen and I usually send emails). You can periodically check their website for deadlines / openings.
(2) CCRI has a CNA course. It is not free to students, but they may have some financial aid. AGE 16 is the requirement! $1400 to be paid upon registration.
https://www.ccri.edu/workforce/programs/healthcare/CNA.html
(3) Brown Health has some CNA courses, but you need to be 18 for these:
There are also some nursing home communities that offer free CNA courses to high school seniors who will be 18 years of age, but they ask that the student work there 1+ years after they receive their CNA.