Orientations of moduli spaces for Legendrian contact homology

I will give an introduction to Legendrian contact homology, which is an invariant of Legendrian submanifolds that is defined by using pseudo-holomorphic disk techniques. In particular, I will explain how one can define this homology with integer coefficients by orienting the moduli spaces of the pseudo-holomorphic disks. I will also discuss how one can make this invariant more easy to compute by replacing the pseudo-holomorphic disks with gradient flow trees, and how the moduli spaces of these trees can be oriented in a computable way.