Draw 2 vertical lines, one through x=-4 and one through x = 3. Next, graph y = x+4. You will see that this sloping graph intersects the lines x=-4 and x=3. Darken your graph for [-4,3] and then you'll be half done here.
Do the same for the other part of the function: graph y = 2x - 1 ONLY for x=3 (touching x=3) to x = 6 (not actually touching x= 6). Done.
This is called a "piecewise function," because it has two distinct and different pieces.