To convert a hybrid into a discrete Bayesian network, please select all nodes (CTRL-A) and then right-click on any of the selected nodes and select Change Type/Chance-General from the node context menu. The resulting network will be an auto-discretized equivalent of the original network. Of course, it is possible to convert only a part of the network by selecting a subset of nodes to be converted.
For example the following network:
will be converted into the following discrete network:
