There are lots of ways to do it, most pretty easy.  For feathers, you can either poke them into firm mash before it has dried or drill fine holes in which to insert the quills.
Hair is a bit finicky.  One way is to take a small bunch in your fingers, trim the end if necessary, dip them in a blob of a quick drying glue and push them on to the surface.  Wool, fur fabric etc is easier to handle.  The glue method should be fine.
Have fun
DavidO