To be honest, I'm not sure which four steps your teacher is referring to. However, I'll show you one way to graph this.
A graph is simply a collection of points. Often those points are connected in some way (though they don't necessarily have to be) to form a curve.
Each point is of the form (x,y). To get each point, we pick random x values and determine their paired y value counterpart.
For example, if we pick x = -3, then,
y= -x^2 -4x -3
y= -(-3)^2 -4(-3) -3
y = -9 - 4(-3) - 3
y = -9 + 12 - 3
y = 0
This indicates that (-3, 0) is one point on the curve.
Let's repeat for x = -2
y= -x^2 -4x -3
y= -(-2)^2 -4(-2) -3
y = -4 - 4(-2) - 3
y = -4 + 8 - 3
y = 1
So (-2, 1) is another point on the curve.
Repeat this process as many times as you want. You should do at least 3 or 4 points in my opinion. The more points you generate, the more accurate the curve. After generating the points, you'll plot them all on the same xy grid. Then finally draw a curve through all of the points as shown below.
I used GeoGebra to make the graph.
