Obstruction bundles for symplectic geometers

When considering pseudoholomorphic curves, we often assume things about an almost complex structure to guarantee that some moduli space is nice. If we need to deal with moduli spaces which are not nice, we can sometimes reduce the problem to the study of sections of an obstruction  bundle. I'll give an overview of how we can build these bundles, based on a recent paper of Doan/Walpuski.