Mathematically, interpreting models with non-linear relationships is the same. However, it is substantively more complicated because knowing whether an increase in X will lead to an increase or decrease (and to what extent) becomes dependent on much more context.  

For this class, it is best to examine a plot, create hypothetical examples and calculate the expected values using observed values that make sense, and use deductive reasoning.

Note: Some non-linear transformations change the interpretation of the intercept, but that change is beyond the scope of this class.