Repeat the data upload, ready, download, delete workflow for data objects, verifying that the ACLs work as expected for different users (e.g. share an object with your neighbor). Provide a number of data objects/records to play with.
Try various queries over the data object and data record resources to understand the filter syntax and learn how to select the resources that you want.
Create data sets that group the objects and records. Verify that the data sets are visible in the UI and that they contain the objects and records that you expect.