Newby Question on fresh caught fish and equipment

I've haven't been fishing since I was a teenager. Even then it was all
Catch and Release. I've decided that I would take the hobby back up, but
would like to keep, and cook my catch. I was wondering what the best way of
storing a freshly caught fish was. Do I kill it on the spot? Do I just
throw it into a cooler w/ ice? Do I try and keep it alive underwater until
I'm ready to go home? I plan on fishing fresh water ponds/ and maybe some
rivers in RI area.

Thanks,
Sam