To roast a chicken you don't put it inside a pot, but near the fire. The same with any meat or even vegetables. You can roast an ear of corn for example. To bake is inside an oven or another kitchen utensil like the Dutch oven. When we cook chicken, pork, etc. we can stew or boil them, mostly. We use the verb to cook in a general sense (to prepare a food). To roast is cooking by approaching something to a source of heat (chicken, ribs, a pig, fish, etc), like barbecue, for example. This is my opinion.
Here is a previous thread that might help, or it might confuse you more. Personally, I might roast meats and vegetables or I might bake them. It depends on what I am making and which cooking method sounds best to me in context.
The Dictionary and thread title search box at the top of the page is a wonderful tool. You can put in words, phrases or word pairs and it will return a list of threads with the search terms in the title, bake roast for instance.