x-intercept is when y = 0
0 = -1/2x - 2
1/2x = -2
x = -4
x-intercept = (-4,0)
y-intercept is when x = 0
y = -1/2(0) - 2
y = -2
y-intercept = (0, -2)
(note that in the form y = mx+b, b is the y-intercept, so in y = -1/2x - 2, -2 is the y-intercept)
Now to graph, simply plot these two points (-4, 0) and (0, -2) and draw a line between them.
Best of luck!