yup that is all i do they are super easy to keep. No logs needed at least for mine the pupate just fine where they are. You can add them if you like , I believe I have read that Orin has had good luck with logs.. I add some decorative brush for looks and to help them right them selves but for sub they are not picky ... just make sure your to separate your grubs once you start seeing trails.
They do pupate in logs in the wild but mine have payed no mind to them in my care.
They very simple to keep Let me know if i can help in any ways what species are you keeping?