...FSD = "Full Self-Driving capability". This means you will get all available released features for your car.
Mainly, you will be able to activate navigate on autopilot on the highway, and on non-highway streets you will have Traffic Light and Stop Sign Control, meaning the car will more or less smoothly stop and go in response to those controls, but if not following a lead car you will have to confirm green light passage by tapping the stalk.
However, at the moment you [may] not be able to request the thing most people really want, which is "FSD beta".
That is the big feature that will navigate around town for you, make turns and change lanes to follow the route, and does not require confirmation to proceed through green lights. Still requires supervision, but on a good day and a good route will basically do all the driving with you lightly holding the wheel and being ready to intervene if needed.