Setting Up a Project in Unity 3D

You can use the Leap Motion SDK as a Unity plug-in to access Leap Motion
tracking data in a Unity application. This article describes both how to
use the plug-in mechanism supported by the Pro version of Unity and how to
manually copy the libraries to use the free, standard version of Unity,
which does not support native library plug-ins.

^{Link to full article:}
https://developer.leapmotion.com/unity/#100