A plotter is somebody who outlines a story before writing it. A pantser tends to "write by the seat of their pants" and figures it out as they go. There is no right way or wrong way. Some people are more analytical and like to delve into details before they start, others don't. There are all levels of each of these, but we each have to find what works for us. Do what feels right to you. Try a little of both if you're feeling stuck.