In every hub there should be a hub text. In the hub text you describe what will happen at the hub, what the participants are expected to learn and how that will be done. You can relate to what they learned in the previous hub and also to how what they are about to do now is related to what comes next. If you want to, you can choose to work with film or sound in the hub texts. This will make it even clearer that you are guiding your participants forward.