Am I using my HEB comal correctly?

I had a nonstick comal (tortilla griddle) for the longest time. Even though my body is probably full of PFAS, I decided to change it and got a Cocinaware cast iron comal. I preheated it in medium heat (same as I did with my nonstick comal) and heated up some tortillas. Immediately the tortillas got stuck and burned almost immediately. Did I do something wrong? Should I use a lower heat?