matt on 21 Dec, 2018 06:35 AM
There isn't an automatic way to shade the top third of an elevation range - you need to look at the contours on the map and figure out the elevation range you're interested in.
Then, click + Add New Layer -> Add DEM Shading. Give the layer a name, check the elevation box and enter the range, pick a color or color range, and click add rule. Similarly for aspect, check the aspect box and choose a range (can be combined with the elevation range, not clear if you want those shaded separately) and enter that as a rule. Then click save.