On your graph, you have the y axis (up and down) and the x axis (left and right).
The equation says y and +4, so start by making a point on the positive 4 on the y axis.
For the slope, you have to use rise over run.
run will always equal to 1
we only have the variable x in the equation, so x will also equal to 1.
Slope = (rise/run) 1/1 = 1
Hope this helps