Raster GIS, External tools menu for the currently available options.
These use a batch file that will be in c:\mapdata\temp. If the operation fails, run the batch file in a command prompt and watch the failure messages.
Get installation from OSGeo4W
To get GRASS extensions, use the option on the File menu from a DEM map
Currently set to use GRASS78; inital attempts to swith to GRASS82 did not work in terms of setting the environment
http://grasswiki.osgeo.org/wiki/QGIS_GRASS_Cookbook
last revised 8/10/2022