There is a lot of information contained in a graph, in the graph below an object moves at a constant velocity for 5 seconds then stops and waits for 15 seconds.  The object then returns back to the starting point.  What else is the graph that isn't so apparent.  The velocity of the object at any time is the slope of the graph at that point.  The slope for the first 5 seconds is 2 m/s (rise over run, the rise is 10 meter the run is 5 seconds  10 m /5 s  = 2 m/s) .  For the time between 5 and 15 seconds, the velocity is 0 m/s (rise over run, the rise is 0 meter and the run is 10 seconds  0 m /10 s = 0 m/s).  For the last ten seconds the rise is -10 meters and the run is 10 seconds 10 m / 10 s = 1 m/s.  There is a lot of information contained in a graph, in the graph below an object accelerate for the first 5 seconds then moves at the same speed for the next 10 seconds.  After that the next 10 seconds the object is accelerated again (this time it's negative).  Then the next 5 seconds it moves at a constant velocity (a negative velocity), and then finally a positive acceleration until the object stops.

1.  The object "stops" or has a zero velocity 3 times, once at the start, one at the end and once a 20 secs.
2. The object moves at a constant velocity twice; once between 5 and 15 seconds.  The second time is between 25 and 30 seconds.  The first time the object is moving away (Positive velocity).  The second time the object is moving towards the starting point (Negative Velocity)
3. The Acceleration between 0 and 5 seconds can be determined finding the slope.  The rise is 10 m/s and the run is 5 s, so the slope is 10 (m/s)/ 5 s or 2 m/s/s.  From 15 to 25 second the rise -25 m/s and the run is 10 s, so the slope is -25 (m/s) / 10 s or -2.5 m/s/s.  The last section, the rise is 15 m/s and the run is 5 seconds or 15 (m/s) / 5 s or 3 m/s/s
4. The last bit of information is the displacement, the area "under" the curve represents the displacement of the object, for the first 5 seconds, the area is (10 m/s x 5 s) x 1/2 or 25 m, why the 1/2 you ask, well 10 m/s x 5 s is the area of a square, the 1/2 gives me the area of a triangle.  From 5 s to 15 s the displacement is 10 m/s x 10 s = 100 m, so from 0 to 15 the total displacement is 25 m + 100 m = 125 m.  We can do it for the rest but the important part is after 20 seconds the displacement becomes negative.   