U don't need to be an expert to learn dodge n burn...More importantly...you must be able see from the picture where u need to burn in the details, dodge out certain areas...
Please being new is no excuses to research on the techniques on dodge and burn using google. Good luck!
both can be used to achieve contrast adjustment - the two methods just offer different levels of control. Dodging highlights and burning shadows is to add contrast to different parts of a pic selectively. Adjusting levels can be used to balance/fix highlights, shadows and midtone values in a pic to add contrast - but unless you go through the effort of masking (or selecting areas that you want/don't want) - it does this to the entire image.