Like @murka243 said, it is essential that you do some research. It is still important to be able to get the literal meaning of the poem but on the other hand, you also need to figure out if there is meaning behind the verses. When you do your research, make sure that you also find other Frost poems so that you can practice finding both meanings. Doing this will pay off when you have to do your commentary as you'll be able to identify more elements and be able to make more comparaisons. Hope this helps!