Pat, this is a very difficult question to answer because some "hands-on" experience can go a long way in expaining how to do it. But I will give it a go.
For light dents, put a fairly damp cloth over the dent and then go over that with a steam iron set on high. You can pull out a lot of shallow dents this way.
For actual chips of wood missing, and if they are faily small, a shellac burn in set, available at Woodcraft stores or their mail order, is probably the best place to start. Using this on a vertical surface is tougher than on a horizontal one. I suggest taking some scrap wood (any kind) and making a chip with a chisel, then practice with it until you get the feel. When you think you have some feel for the tool, select a color stick that is lighter than the wood color you are trying to match and fill in the chip with the shellac.
Next, sand the repair flat. Use a small sanding block for a small area and 400 or 600 wet or dry paper. Use a light hand for this too. It is very easy to end up having to repair a much larger area than the one you started on.
Now start blending the colors. Most of the wood used for moldings is red oak, not white oak. All wood is a blend of many colors. Use the "magic marker" type stain sticks available from Minwax at home centers and tone sprays, available from Woodcraft to blend your repair into the surrounding wood. Again use a light hand with the tone spray and smear the stain stick colors with your thumb to get as close to the parent wood as you can. Nature and wood doesn't have straight crisp lines.
Red oak will have some tans, light browns, oranges and blacks in it. Really look closely at your wood and you will see a lot of different colors. This is the effect that you will be trying to match. If you go much to heavy with the color, you can use some mineral spirits on a rag to take the stain stick color off and start over.
When you are satisfied with the color and it is dry, mist the area a couple of times with a spray lacquer, waiting about 20 minutes between coats. Matching the amount of shine on your parent wood to the repair area is the biggest single step to making a wood repair unnoticeable. You will not be able to tell this while the lacquer spray is wet and be sure to shake the can well before each mist coat. This will work well with anything except a water based poly final finish. If you know that you have that, use a brush on water based poly for the final finish steps and do the whole piece of molding.
When using any of the sprays, mask the walls and floor with newspaper or cardboard.
Other than some of the early "The Furniture Guys" shows like "Furniture To Go" and Furniture On The Mend" there is not much available on TV to show you how to do this process. If you do happen to catch one of them, it does help to be able to see the process done first. It is a lot more art than science.