Cannot open Capella image


I am trying to open a stripmap SLC image from Capella with Import>SAR Sensors>CAPELLA. The importer says it can handle .json files. I have the extended.json and json file in the same folder as the GeoTiff image. When I double click either on the extended.json or .json file, only metadata are loaded. How can I get the bands from the GeoTiff loaded and recognized as part of the Capella dataset?

Thanks in advance!