No prob. Let's use the "beard" part of your sculpt as an example.
1) A "wash" is simply a diluted paint application in which you basically
flow the paint into all of the nicks and crannies, if you will. Make sure the paint is a darker variation of the initial color applied. Allow it to dry fully. You are most probably using acrylics, so make sure it's very "thinned", meaning there's more water or thinner than paint. it will flow better and not gob up the beard.
2) Dry-brushing is simply using a ligher variation of the initial color but instead of it being diluted, you want it to be slightly thicker BUT pick up just a tiny dab with your paint brush's tip (use a flat brush for this). Now brush off most of the paint on a piece of paper towel or old rag. Make sure hardly any paint shows up on the rag and now very gently wisk just the tip of the brush over just the higher points of the sculpt. At first you may see nothing but as you keep passing the tip over the high points, the lighter color will start to accumulate on the raised parts of the beard. The secret is to know when to stop. Just when you think it could use a little more, STOP!
But if you do go over-board with the dry-brushing, simply apply the original color again, let dry, and then do the dry-brushing once again.
The combination of the darker wash color in the cavities, the original color overall and the lighter color of the dry-brushing will provide a fantastic 3-dimensional effect on your sculpted beard (or hair, etc...)
You may want to try it first on an old sculpt for practice, but it's really not that hard to make it look good.
Give it a go!
