Calculate the slope and aspect values from DEM using ArcGIS 10.3

This video tutorial give you the solution to how you can Calculate the slope and aspect values from DEM using ArcGIS 10.2. If you need to calculate the percentage of the area of each exposure you can do this steeps :

with a categorical raster data, you can build the raster attribute table of your raster. Once this is done, open your table (right click on the layer) and you will see the count of the pixels. Multiply by the area of your pixels and you have a good approximation of the area of each class.OR use ERDAS and calculate the area