Accept the FaceFX Runtime End User License from here. Full text (without logging into facefx.com) also available here. The FaceFX Runtime is free on the PC platform for non-commercial and educational use, and free for the first $500,000 for indie games. Games that will make over $500,000 or require console support need to contact us for a commercial license
Install the FaceFX Runtime compiler Python plugin into your FaceFX Studio installation by following directions in the plugin README.md. It is located in the facefx\tools\compiler\plugin folder or the FaceFX\Source\FaceFXLib\facefx-runtime-2.1.0\facefx\tools\compiler\plugin folder depending on the distribution downloaded above.