Hey guys let see if you can help me, I am trying to skinned a product, with carbon firbre, I was told to add catalyst to epoxy. Do this really needed? what is the sense of adding catalyst to epoxy if the epoxy is a laminar glue

Thank you very much for your quick responds...
According to the seller, he told me that the epoxy contain 3 component, that there is no need for catalyst. I am new to firbre carbon and epoxy, I would like to be sure of what I am doing before I made a mistake