Given that Y = X + 2, you can make a table of values for Y with a given value of X. In your example, when X = -3, Y will equal X + 2 which turns out to be -3 + 2 = -1
In this case Y = -1 and X = -3. Looking at different values for X, we get
when X= -2, Y will equal 0
when X = -1, Y will equal 1
when X = 0, Y will equal 2
when X = 1, Y will equal 3 and so on
You can then plot those values on a graph.