Rig

Go to the side panel (N) > Facial Tools > Rigging

Select your character's head and eye(s), then hit "Auto-Facial".

There might be some bone tweaks to be done depending on the character model.

NOTE: you must be in edit mode to edit bones.

Export

To export your character facial to a game engine or whatever, go to the side panel (N) > Facial Tools > Misc > Export.

Select the character meshes and the rig, hit export and save on the path where you want it to be saved.

Bind

To bind, just go to Facial Tools > Binding.

Choose the binding mode you want, tune settings if needed, select your character meshes and then the rig, and finally hit "Bind!".