There are two possibilities, how to integrate and enable the glTF 2.0 exporter into Blender:
One possibility is to set this folder as the Scripts folder.
For this, open the User Preferences... dialog in Blender.
Switch to the File tab and set the Scripts entry to this folder.
Advantage is, that any update/pull to the exporter is automatically visible by Blender. Drawback is, that the Scripts folder is just used for the glTF 2.0 Python modules.
Otherwise, copy the io_scene_gltf2 folder to the scripts/addons folder of your Blender installation.
In both cases, enable the glTF 2.0 exporter under the Add-ons tab.
