Downloading Landsat 8 ARD data in s2tbx

Would some one please describe the procedure for downloading Landsat 8 ARD data in the S2tbx? The band format is tiff, and the individual bands can be imported, but images cannot be displayed.

The Landsat ARD dataset is not yet supported. You can’t open products vom this dataset in SNAP.
More specifically most of the GeoTiff files use a type of compression which is not supported.
Probably you can convert the files, with gdal for example, and then open them in SNAP.