Why reading and understanding previous works is an important part of the research process?

If you are given an assignment to perfrom a task that you have not undertaken before; one logical way to understand the requirements of that task is to perform research analysis by reading books and/or articles that contain bona fide information pertaing to that task. In some cases, the results derived from internet research can act as an adjunct to information obtained by books and/or articles.

As a simple example, let's say that you are requested to bake a black Forrest cake; something that you never did before. One logical approach, without having to purchase a cook book, would be to search the Internet for "Black Forrest Cake" recipes and once you found one that appeared to be easy to follow, you would then simply bake the cake by following the steps contained in the recipe. In this example, you did perform some research; however, it wasn't really necessary to "understand" what you were doing.

As another example, if you were assigned the task of building a mini racing car and didn't understand the principles of auto mechanics; then, you would have to both read and understand the principles of auto mechanics before attempting to build the racing car.

I hope that my answer to you question has been helpful.