Regular Bayesian networks are purely statistical models, so we can only talk about the flow of association in Bayesian networks. Association still flows in exactly the same way in Bayesian networks as it does in causal graphs, though. In both, association flows along chains and forks, unless a node is conditioned on. And in both, a collider blocks the flow of association, unless it is conditioned on. Combining these building blocks, we get how association flows in general DAGs. We can tell if two nodes are not associated (no association flows between them) by whether or not they are d-separated.