BDC provides general information about accessing hosted data on the Explore Data in BDC webpage and, from there, links to several resources helpful for getting an eRA Commons account (required to access open and controlled data) and submitting data access requests (needed to access controlled data).
Researchers who already have approved DARs for the datasets of interest to them do NOT need additional permissions to access them through BDC.
Neither eRA Commons accounts nor approved DARs are required to explore the data BDC hosts, and users do not incur costs for exploring data in BDC.