a). The height of the line above the x-axis tells you how much
distance you've covered. (That may or may not tell you about
your location if, say, you traveled zig-zag.)
b). The slope of the line at each point tells you about the speed
at that moment. (It doesn't tell you about the velocity, because
the graph doesn't tell anything about direction.)
c). If the graph is curving up, then it means that the speed is
increasing. That's positive acceleration.
If the graph is curving down, then it means that the speed is
decreasing. That's negative acceleration.
(There's one kind of acceleration that the graph won't show.
If the motion is keeping a steady speed but changing its
direction, that's the 3rd kind of acceleration, but you don't
see it at all on the graph.)
d). Speeding up . . . . . the graph is curving up.
Slowing down . . . . . . . the graph is curving down.