 Hello! In this video we're going to clip a raster using a mask. In this case we'll clip the DEM with the bounding box polygon. The DEM and the bounding box have the same projection. Go to the raster menu, extraction, clip raster by mask layer. Make sure that the input layer is to re-project the DEM with the projection that corresponds with the bounding box. If projections are different, QGS might convert it in the background, but it's good practice to keep them the same. Check the box to keep the resolution of the input layer, so the output will have the same resolution as your input DEM. Then save the result to a GeoTiff. Let's call it DEM subset. Note that it will run JiddleWarp again that we also used in the previous step. These steps can be merged. Uncheck the box for the big DEM to see how the subset has been clipped. This is the result, so in this video you've learned how to clip a raster layer using a mask polygon layer.