Part of the deal with Wave is that you need to edit and mess with routinely the JSON files that power all the functionality. If for example you want to bring in new fields or objects into Wave, you can either:
Attempt to edit the JSON file for a particular dataset (hmmm)
Edit the jSON file for the who Dataflow.
Unless you have some massive datasets, its probably the easiest just to edit the dataflow’s JSON file.
Pretty easy to get there. Its within the gear icon labelled Data Monitor
Switch over to Dataflow View
Scroll down to the Dataflow you want to monkey with and click “Download”
Obviously once you download and edit it, you need to upload the updated file for it to take effect. Fortunately the link to upload is there as well.
IF YOU WANT IT TO TAKE EFFECT IMMEDIATELY – then you need to rerun your dataflow. Otherwise the new settings will take effect on the NEXT run.
Be aware that if there is an existing dataset for an object that your edits here will NOT affect security. For that you need to edit the dataset itself and update there. (Thats true as of March 2016)