Where to put carbon in my filter.

[fishychuck]

I’m sort of new at this. 2 months. I’d like to optimize my filter. I’m currently using filter sponge, carbon, and poly fiber, filter floss. I have the carbon just laying in the bottom of my filter. Are bio rings really worth having? Is it ok to keep the carbon there or should it be in a mesh bag or?
Thanks for all replies. CM